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Karteikarten von Alex Obray, aktualisiert more than 1 year ago
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Erstellt von Alex Obray
vor fast 9 Jahre
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| Frage | Antworten |
| 1. What is matter? Draw a diagram of the classification of matter | Matter is anything that has mass and occupies space. It can be it can be divided into groups: pure substances and mixtures. |
| 2. What are pure substances? What are they referred to as in chemistry? | Only only type of matter present in the sample A pure substance has a constant composition: all parts of the substance are the same. This means that their properties also remain constant. In chemistry, pure substances are referred to as chemicals. For example, copper and methyl alcohol are pure substances. Pure substances can be divided further into compounds and elements. Compounds are molecules made up of more than one type of atom, such as H2O or NaCl. Elements are made up of the same kind of atom, such as Ca or Br2. Only one type of compound is present in a sample. |
| 3. What are mixtures? What are homogenous mixtures referred to as in chemistry? | Mixtures of more than two substances Mixtures display varying properties as the proportions of the components in the mixture change. Mixtures can be divided into two groups: heterogeneous and homogeneous. In homogeneous mixtures, all parts look the same. e.g (the sample you took would be uniform throughout the entire sample) e.g. tomato sauce is made up of tomatoes, vinegar, salt and spices, but you can't see these parts individually in the mixture, although with a microscope you could see particles of tomato skin and pepper flakes. In chemistry, homogeneous mixtures are often referred to as solutions. For heterogeneous, the mixture is not uniform throughout. (There is an interface between the two substances that make up the mixture .e.g depending on where you take the sample, you could end up with a different substance They are made up of parts that can be macroscopically distinguished in the mixture. For example, relish is made up of cucumbers, vinegar, red peppers, mustard seeds and spices. It is possible to see each one of these ingredients in the mixture. |
| 4.What is an atom and what makes up an atom? | The atom is the smallest particle of a chemical element that can exist on its own, and that retains its characteristic chemical properties. It is made up of three main components (sub-atomic particles): nucleons (protons and neutrons) forming a dense nucleus in the centre of the atom as the electrons travel around the nucleons at 3/4 the speed of light. The force of attraction between electric charges binds the electrons in an atom |
| 5. What determines an atom? | The amount of protons and electrons it has |
| 6. What is an ion? | Species in which the number of electrons does not equal the number of protons. (so the atom/molecule has a net charge) An ion is an atom that has lost or gained electrons. A positive ion is called a cation, and a negative ion is called an anion. Thus e.g. when a sodium atom loses an electron (which is a negatively charged particle within the atom) |
| 7. What does the atomic number correspond to and what is it represented as? What can it also respresent? | The atomic number of an atom corresponds to the number of protons the atom has. For a neutral atom, it is also equal to its number of electrons. The atomic number is represented by the letter Z. |
| 8. What is the mass number and what is it represent as? | The sum of the number of neutrons and protons in an atom. Represented as letter A |
| 9. The number of neutrons in a given atom can be calculated using the formula | Neutrons = mass number – atomic number = A - Z |
| 10. Iron has an atomic number 26. Its mass number is 56. The number of neutrons it contains is: | = mass number – atomic number = 56 – 26 = 30 Therefore, iron atoms have 30 neutrons. |
| 11. What is an isotope? How are they named? | are atoms of an element that have the same number of protons but different numbers of neutrons. Isotopes are named by stating the element's name followed by its mass. |
| 12. The element carbon has 3 isotopes: carbon-12, carbon-13 and carbon-14. How many neutrons do they have? | Since all carbon atoms have 6 protons, carbon-12 has 6 neutrons, carbon-13 has 7 neutrons and carbon-14 has 8 neutrons. |
| 13. What element has the most amount of isotopes? | Tin. It has a total of 38 possible isotopes! |
| 14. What does the nucleus determine? | The atomic mass and configuration of electrons |
| 15. What is C-13? What is C-14? | It is a stable atom but much less common on our planet compared to C-12 Unstable form of carbon which will decay or change to C-12 releasing radioactive energy - this is a raidosiotope of carbon |
| 16. How do the properties of isotopes compare to one another (e.g. isotopes of carbon)? | Same number of protons, chemical properties, physical properties (Except small differing mass) You could eat both with the same result (radioactive isotopes having varying effects on the body when ingested and the release of radioactive energy has many important medical applications) |
| 17. Why is the average mass of carbon not the mean of 12 + 13? | Because C-12 is much more abundant on earth or in any random sample of element. |
| 18. There are two isotopes of helium in the sample, representing the distribution of helium on this planet: There are three He-4 atoms for ever He-8. What is the relative atomic mass of helium, as measured in atomic mass units? | 5.000 a.m.u. (4+4+4+8)/4 |
| 19. Carbon exists in two forms: C-14 and C-12. Which statement is true of carbon? a) C-12 forms carbon monoxides and C-14 forms carbon dioxide b) the atomic mass of carbon must be more than 12 c) C-14 is more reactive than C-12 d) Both forms of carbon have the same number of neutrons e) none of above | b) |
| 20. Random sample of element has 75% of its atoms weighing 35 and 25% weighing 37. What is the relative atomic mass? | (35+35+35+37)/4 = 35.5 amu This describes the element Cl (= 35.45 amu) |
| 21. Which of the following is an ion? A) C B) I2 C) HIO3 D) IO3- | D) |
| 22. How many neutrons are there in a silver atom? (silver has an atomic number of 47 and a mass number of 108) a)47 b) 61 c) 94 d) 155 | = A - Z = 108 -47 = 61 |
| 23. Which of the following is a heterogeneous mixture? a) distilled water b) rubbing alcohol c) soil d) apple juice | Soil |
| 24. CO2 can be classified as a (an): atom molecule mixture solution | molecule |
| 25. What is the safety system called? | WHMIS: Workplace Hazardous Materials Information System |
| 26. What do these symbols represent? | flammable substance, biohazardous material, poisonous substance. |
| 27. Elaborate | These symbols are further complemented with a hazard rating system for health, flammability, and physical hazard. The system utilizes coloured bars, numbers and symbols to convey the hazards of chemicals used in the workplace. Each one of the three sections is given a rating from 0 to 4, where 0 represents no danger and 4 represents the highest degree of danger. The bottom section of the label indicates the personal protective equipment that should be worn while using that chemical; a letter is used for this part, and the higher the letter, the more protection is needed. |
| 28. | Here, ethanol is attributed a health hazard of 1, a flammability of 3, and a physical hazard of 0. The level of personal protective equipment (PPE) is C. This means safety glasses, gloves and an apron should be worn when working with this chemical. |
| 29. What is MSDS? | Along with these symbols, Material Safety Data Sheets (MSDS) are given to the employer to keep in a binder and to be reviewed by employees in training. These sheets are also in school laboratories. They must be easily accessible to all staff and kept up to date, as they list important information about the chemicals used, including: product information hazardous ingredients physical data fire and explosive data reactivity data toxicological data preventative measures to be taken when using the chemical first aid procedures |
| 30. | Class A Compressed Gas |
| 31. | Class B Flammable and Combustible Material |
| 32. | Class C Oxidizing Material |
| 33. | Class D 1. Materials Causing Immediate and Serious Toxic Effects |
| 34. | Class D 2. Materials Causing Other Serious Toxic Effects |
| 35. | Class D 3. Biohazardous Infectious Materials |
| 36. | Class E Corrosive Material |
| 37. | Class F Dangerously Reactive Material |
| 38. | |
| 39. How long has the periodic table been around for? | Less than 150 years |
| 40. Who organized the periodic table in almost the way we view it today and when? | In 1869, a Russian chemist named Dmitri Mendeleev came up with a way of organizing the elements that were known at that time. He placed them in order of their atomic weight and then grouped them into rows and columns based on their observed chemical and physical properties. Mendeleev had no idea what atoms were made of or why they behaved as they did, however, he was able to put together the periodic table almost as we know it today. His periodic table had gaps in it since some elements were unknown at the time. Based on the gaps in his table, Mendeleev even succeeded in predicting the existence and properties of several new elements e.g. Galium, Scandium, Germanium, Rhenium, Technetium |
| 41. What are the columns and the rows of Mendeleev's periodic table called? | The columns on his periodic table are called groups or families, while the rows are called periods. |
| 42. What is the the periodic table of the elements? What is the periodic law? | Is a table in which all of the known chemical elements are arranged in order of their number of protons. Elements with similar chemical and physical characteristics are grouped in regions within the table. This is known as the periodic law |
| 43. How many families is the periodic table divided into? | Into 7 families. The main families are the alkali metals, alkaline earth metals, transition metals, lanthanides, actinides, halogens, and the rare gases. |
| 44. In what general area are the metals located on the periodic table? left right top row in the middle | Left |
| 45. Where are the halogens located on the periodic table? group 1 group 2 group 17 group 18 | Group 17 |
| 46. Where are most of the gases located on the periodic table? left right middle top row | Right |
| 47. In what general area are the non-metals located on the periodic table? left right top row only in the middle | Right |
| 48. Has any elements been discovered by Canadians? | Although no elements have been discovered in Canada, there are Canadian connections. Element 104, Rutherfordium, is named in honour of Ernest Rutherford. In 1898 Rutherford was appointed to the chair of physics at McGill University in Montreal, Canada, where he did the work that won him the Nobel Prize in Chemistry in 1908. |
| 49. Where are electrons found in an atom? What indicates the energy levels of an element on the periodic table? | Travelling around the nucleus in energy levels. An element's row on the periodic table indicates how many energy levels it can have. |
| 50. Where are electrons with higher energy located in an atom? Who proposed this? Is there a limit? | At higher energy levels Neils Bohr proposed that e-s were found in discrete energy levels. There is a maximum number of electrons that can be in each energy level |
| 51. How many electrons can H and He have in their energy level? What about elements 3 to 20? | a maximum of 2 Up to 8 electons in the highest energy level (E.g. potassium |
| 52. What is the name for electrons located at the highest energy level? What do they determine? | The electrons located in the outermost, or highest, energy level in an atom are called the valence electrons. Their layout determines the chemical element's behaviour (e.g. the number of valence e-s effect the way it can combine with other atoms to form compounds). Also, the layout of the valence electrons from elements in a common group is identical; there are more shells as you go down the group but the outer shell structure is identical. |
| 53. What is a general rule you can use to determine an atom's valence electrons? | Although there are exceptions, a general rule you can use to determine an atom's valence electrons is its corresponding group on the periodic table. Elements from group 1 have 1 valence electron, group 2 have 2, group 13 have 3, group 14 have 4 and so on. Group 18 have 8 valence electrons, thus giving them a full valence shell, which is why they tend to be so stable and non-reactive. |
| 54. Although properties for elements within a column in the period table are similar, what differs? What is it called? | The intensity of these properties differ. This is called the activity series which is a list of substances ranked in order of decreasing reactivity |
| 55. List the elements of the activity series | Potassium is the most reactive and gold is the least reactive Potassium Calcium Sodium Magnesium Aluminum Zinc Iron Cobalt Nickel Tin Lead ---------------- Hydrogen ---------------- Copper Mercury Silver Platinum Gold |
| 56. How much gold has been obtained by humans? | It is estimated that the total amount of gold obtained by humans is only 116 000 metric tons. That is an 18 metre cube of gold! |
| 57. Elaborate on alkali metals regarding to reacting to air What can you tell you about the activity series for the alkali metals? | These are metals that you can cut, revealing their metatallic lustre, however, when alkali metals are exposed to air, compounds quickly form on the metallic surface as the coating quickly reappears (corrosion). The reactivity of the alkali metals increases from lithium to sodium and the most reactive of the three is potassium |
| 58. How do alkali metals such as lithium and sodium react with water? | For lithium, the metal floats on the water, reacting and giving off hydrogen gas. For sodium, the same thing happens but a more vigorous reaction occurs where all other alkali metals react the same way. Hydrogen gas is produced and the metal dissolves into an aqueous cation with a single positive charge. |
| 59. How do potassium, rubidium and cesium react with water? | The heat given out by the reaction is produced so quickly, the hydrogen catches fire, burning. This is more explosive as you go down the group e.g. rubidium and cesium |
| 60. Do metals react with water? | Many metals can react with acid but only a few can react with water. This reaction displaces the hydrogen from the water molecule and the liberated hydrogen gas bubbles out of the liquid. |
| 61. What type of acids react with metals and what do they liberate? | Acids such as hydrochloric acid, or sulphuric acid, are much more reactive than water and many metals can react with them to liberate hydrogen gas from the acid |
| 62. What occurs when a metal (e.g. a coin) interacts with a solution made of a metal lower in the activity series? What occurs in an opposite situation? | A precipitation reaction will occur where the dissolved metal (e.g. nickel or silver for silver nitrate (AgNO3) or nickel sulphate (NiSO4), respectively) will come out of solution and form a solid precipitate, but the reacting coin will dissolve into the solution. If the metal is lower in the series than the metal in the solution, no reaction will occur. |
| 63. Which of the following is a metal? carbon vanadium fluorine xenon | Vanadium |
| 64. Which of the following is a metalloid? carbon phosphorus tin antimony | antimony |
| 65. A chemist is working with four substances: nitric acid, silver, magnesium and aluminum. Which one of these is the most reactive? nitric acid silver magnesium aluminum | Magnesium |
| 66. How many valence electrons are there in a carbon atom? | Four |
| 67. What is a period trend? (First, relate it to valence electrons, then define it) | Elements within a group have the same number and distribution of valence electrons. This gives them similar properties; however, these properties are not identical. Instead, there are variations of these properties within a group. These are called periodic trends. Periodic trends are specific patterns that are present in the periodic table that illustrate different aspects of a certain element, including its size and its electronic properties. |
| 68. What are the most common trends of the periodic table? | Atom radius - The distance from the center of an atom to its outermost edge. Ionization energy - The amount of energy needed to remove an electron from an atom. Electron affinity - The energy change that occurs when an atom gains an electron to form a negative ion. Electronegativity - A measurement of an atom's ability to attract electrons. |
| 69. What are alkali metals? | Alkali metals comprise of elements found in group 1 of the periodic table: Hydrogen, Lithium, Sodium, Potassium, Rubidium, Cesium and Francium. They are grouped together due to the shared characteristic of containing only one electron in their outermost shell. In addition, they tend to lose their valence electron, forming a cation of charge plus 1 (with hydrogen being the exception, exhibiting few characteristics and is usually grouped with non-metals). They are malleable, ductile, highly reactive (thus not found freely in nature) and are known to conduct heat and electricity well. |
| 70. What are alkaline earth metals? | b. Alkaline earth metals include the elements found in group 2 of the periodic table: beryllium, magnesium, calcium, strontium, barium, and radium. They all share identical electron configurations, containing two electrons in their highest energy level, corresponding to a full valence shell. Alkaline earth metals have relatively low ionization energies for their valence electrons and are electropositive as a result. They have very high melting points and are rarely found freely in nature due to their high reactivity. |
| 71. What are transition metals? | c. Transition metals consist of 38 elements ranging from groups 3 to 12 and the lanthanides and actinides (which are often referred to as inner transition metals) of the periodic table. They have partially filled d or f subshells, leading to several common oxidation states. Transition metals usually have a high melting point and readily form coloured compounds, sometimes losing different numbers of electrons, depending upon what they’re bounding with and their given environment. |
| 72. What are lanthanides? | d. Lanthanides contain elements lanthanum through lutetium (atomic numbers 57 through 71, respectively) and are grouped with transition metals, although they have differing chemical properties due to their progressively filled 4f orbitals, shielding the atom from the surrounding environment. Lanthanides display a property known as lanthanide contraction whereby the radii of the elements of the lanthanide series decrease progressively, in order of atomic number. The name lanthanide derives from the fact that the properties of the lighter elements closely resemble lanthanum. |
| 73. What are actinides? | e. Actinides comprise elements actinium, through lawrencium (atomic number 89-109) and are f-block elements (lawrencium being the exception). Actinides display a wide array of oxidation numbers and are very dense, combining directly with most non-metals. All actinide elements are radioactive, and are progressively unstable (especially the heaviest of actinides). Only thorium and uranium are represented significantly, occurring freely in nature. |
| 74. What are halogens? | f. Halogens are a subset of the non-metals, encompassing group 17 of the period table, from fluorine through astatine. They generally exhibit high chemical reactivity, readily combining with metal to form salts (hence salt formers) in addition to bonding electrons, readily gaining one extra electron and forming an anion with an overall net charge of -1. As a consequence of their high reactivity, halogens are in the form of compounds rather than pure elements in the environment. |
| 75. What are rare gases? | g. Rare gases, also known as noble gases (“inert gases”), consist of six elements found in group 18: helium, neon, argon, krypton, xenon and radon. Noble gases have a full valence shell of two electrons, making them very stable and seldom interact or form chemical bonds. Thus noble gases are generally monatomic by nature as there are only a few known compounds that involve noble gases (only two of which combine under special conditions). |
| 76. What are metalloids? | h. Metalloids consist of the elements boron, silicon, germanium, arsenic, antimony, tellurium and polonium. Metalloids are also known as “semi-metals” or “poor metals” as they exhibit some properties of metals and nonmetals. Boron, silicon and germanium for instance, behave as semi-conductors which is useful for building silicon chips found in computers and calculators. Although metalloids display a metal-like appearance, they are generally brittle and fragile. |
| 77. What is a chemical bond and how many bonds can an atom have between them? | A chemical bond is a strong force of attraction holding atoms together in a molecule or crystal. Atoms can form 1 (single), 2 (double) or 3 (triple) bonds between them. |
| 78. The human body is capable of manufacturing many molecules, some for survival and others as waste. It is capable of producing molecules with millions of bonds, but what is type of molecule is the body in capable of producing? | It is incapable of producing diatomic molecules with only one bond between identical atoms! |
| 79. What is the octet rule? | Atoms tend to gain, lose or share electrons until they are surrounded by eight valence electrons |
| 80. What is an ionic bond? | An ionic bond is a chemical bond that results from the electrostatic attraction between positive metal ions and negative non-metal ions. As a metal and a non-metal approach one another, the valence electrons interact and the metal (indicated by the red sphere) transfers its valence electrons to the non-metal (indicated by the blue sphere). The metal becomes positively charged through the loss of electrons and the non-metal becomes negatively charged through the gaining of electrons. In this way, both the metal and the non-metal complete their valence shell to obtain a stable electron configuration. (so when one of the atoms has sufficient strength of attraction to remove an e- from other) |
| 81. Example relating to ionic bonds: Sodium has its 11 electrons arranged in three energy levels. Closest to the nucleus will be the first level containing 2 electrons, then the second level containing 8 electrons, leaving 1 electron in the outermost energy level. What is the easiest way for sodium to gain a stable electron configuration? | The easiest way for sodium to gain a stable electron configuration is to donate the single outermost electron to another atom. This will result in a +1 charge for this new entity - a sodium ion (Na+). Therefore, one sodium atom will combine with one chlorine atom to form sodium chloride. |
| 82. Chlorine has 17 electrons, 7 of which are in its outermost energy level. How can it gain a stale electron configuration? | It can readily gain a stable electron configuration by gaining 1 electron from another atom. This means it will have a net charge of -1, and becomes Cl-. Therefore, one sodium atom will combine with one chlorine atom to form sodium chloride. |
| 83. What is the most polar type of bond? | Ionic bonds |
| 84. Do ionic bonds form a molecule? | No, but rather a crystal which has no set size. The crystal lattice structure has cations surrounded by anions and the anions are surrounded cations |
| 85. What is this resultant of sodium and chlorine interacting? | sodium chloride |
| 86. What is a covalent bond? | As two non-metals approach one another, the valence electrons interact. A covalent bond is formed between the two non-metals, which share a pair of electrons so that each obtains a filled valence shell. (so neither has sufficient strength to remove e-s from other atom) Covalent bonds are the most important type of bond occurring in organic molecules. Depending on the involved partners, simple, double or triple bonds can be formed. (The nuclei and core electrons are indicated by the blue spheres and the bonding electrons are indicated by the lavender dots.) |
| 87. What is a polar bond? | a bond in which the electrons are not shared equally between the two atoms |
| 88. What is a non-polar covalent bond? | the electrons are shared equally between the two atoms. The electrons move around the nuclei with the electrons generating temporary positive and negative charges within the molecule. |
| 89. What is a polar covalent bond? | In a polar covalent bond the electrons are shared unequally between the two atoms. In this situation, one atom has a greater ability to pull the bonding electrons towards it and is said to be more electronegative. The electrons move around the nuclei with the electrons spending the majority of the time near the more electronegative element. This generates a partial negative charge near the more electronegative element and a partial positive charge near the less electronegative element. The green sphere represents the more electronegative element.)) |
| 90. What is a covalent compound called? | The nuclei and core electrons are indicated by the blue spheres and the bonding electrons are indicated by the lavender dots. |
| 91. What is molecular polarity dependent on? | Molecular polarity is dependent upon bond polarity and molecular geometry. For small molecules, if all the regions surrounding an atom are similar in their electronegativities, the molecule will be non-polar. If the regions are different, then the molecule will be polar. It is possible to have a molecule with 4 polar bonds, each pulling in their own direction, giving the molecule as a whole a change of 0. This is similar to two teams pulling with equal strength in opposite directions at tug-o-war; the result is no movement. |
| 92. How can you determine the type of bond occurring between two atoms? | By calculating the difference between the electronegativities of the two atoms involved. It should be noted however, that when a metal and a non-metal are involved in the bond, it will be an ionic bond. |
| 93. What can a bond spectrum table be used to predict? | It can be used to predict the most probably type of bond that will result between the two atoms |
| 94. Write the bond spectrum table for covalent (non-polar) bonds being the most probably type | Difference in electronegativity ll Percent Ionic Character 0 l 0 0.1 l 0.5 0.2 l 1 0.3 l 2 0.4 l 4 0.5 l 6 0.6 l 9 0.7 l 12 0.8 l 15 0.9 l 19 |
| 95. Asenic has an electronegativity of 2.0 and selenium's is 2.4. What type of bond is between these atoms? | The difference gives 0.4. Consulting the bond spectrum table, shows that this range indicates a polar covalent bond between the atoms. |
| 96. The bond that forms between a calcium atom and a bromine atom is: a) ionic b) polar covalent c) non-polar covalent d) a hydrogen bond | Ionic since metal and non-metal |
| 97. a) ionic b) polar covalent c) non-polar covalent d) a hydrogen bond | EN = 4.0 - 3.0 = 1.0 Polar covalent |
| 98. What are the properties of ionic compounds? | Contain a metal and a non-metal Have strong bonds Have high melting points Are soluble in water Dissociate into ions in solution Are hard and brittle Most are soluble in polar solvents Usually form crystalline compounds in a solid state All ionic compounds are solids at room temperature Are poor electricity conductors as solids Can conduct electricity when dissolved in a solution or when in a liquid form |
| 99. What are weak interactions? | As two non-metals approach one another, the valence electrons interact. A covalent bond is formed between the two non-metals, which share a pair of electrons so that each obtains a filled valence shell. Covalent bonds are the most important type of bond occurring in organic molecules. Depending on the involved partners, simple, double or triple bonds can be formed. |
| 100. What are intermolecular forces? | Intermolecular attractions are attractions between one molecule and a neighbouring molecule. All intermolecular attractions are known collectively as Van der Waals forces. |
| 101. When was dispersion forces first described? What about for dipole-dipole interactions? | The various different types of forces were first explained by different people at different times. Dispersion forces, for example, were described by Fritz London in 1930; dipole-dipole interactions by Keesom in 1912. |
| 102. Why do metals and ionic compounds have extremely high melting and boiling points? | Electrostatic forces occur between charged species and are responsible for the extremely high melting and boiling points of ionic compounds and metals. |
| 103. All molecules have the capability to form what type of force? | London forces (also known as dispersion forces). They occur in covalent compounds. They result from the movement of the electrons in the molecule which generates temporary positive and negative regions in the molecule. These are the only types of forces that non-polar covalent molecules can form. |
| 104. What are dipole-dipole forces? | Dipole-dipole forces are caused by positive and negative ends of a molecule which attract each other like little magnets. Only polar covalent molecules have the ability to form dipole-dipole attractions between molecules. |
| 105. What is hydrogen bonding? | Hydrogen bonding occurs between polar covalent molecules that possess hydrogen bonded to an extremely electronegative element, specifically nitrogen, oxygen and fluorine. These often occur in organic molecules. It is much weaker than a covalent bond, but in large molecules with many hydrogen bond interactions, the sum of the interactions can be an important determinant in retaining the shape and structure of a molecule, such as protein and DNA structure. |
| 106. Only one of the following lists does not consist entirely of symbols for elements. Which one? a. C, He, Mg, Cu b. H, ASA, P, Fe c. He, N, Cl, O d. Ca, Ne, Fe, He | H, ASA, P, Fe |
| 107. The correct association of the following pairs of terms is given by: a. families are to periods as rows are to groups b. periods are to rows as families are to columns c. rows are to families as groups are to families d. columns are to periods as rows are to families | b. periods are to rows as families are to columns |
| 108. Element number 92 is a: a. gas b. metal c. metalloid d. non-metal | metal |
| 109. Which of the following groups of elements contains only metalloids? a. Ge, As, Sb, Si b. Li, Na, K, Rb c. Ge, As, Ni, W d. Ge, Pb, Au, Ag | a. Ge, As, Sb, Si |
| 110. 6. In the modern periodic table, elements with similar properties appear in the same row. a. true b. false | False |
| 111. Most of the known elements are metals. a. true b. false | True |
| 112. The noble gases are very reactive elements. a. true b. false | False |
| 113. Elements in the same column have the same number of valence electrons. a. true b. false | True |
| 114. Potassium belongs to the group of elements known as halogens. a. true b. false | False |
| 115. In the periodic table, elements with similar chemical properties are found in ______ | groups (or families) |
| 116. Elements that possess some properties of metals and some properties of non-metals are called ____ | metalloids |
| 117. The number of electrons in an atom is the same as the number of ____ | protons (for a neutral atom) |
| 118. In what region of the periodic table are the non-metals found? | Most gases are located on the right of the periodic table. |
| 119. How many valence electrons does an atom of strontium have? | 2 |
| 120. What determines the order of elements in the modern periodic table? | In order of increasing atomic number (i.e. number of protons) |
| 121. State the periodic law. With reference to the physical and chemical properties of the alkali metals, show how this family of metals illustrates the periodic law. | The periodic law states that the physical and chemical properties of elements display a periodic variation when they are arranged in order of increasing atomic number. Alkali metals comprise elements hydrogen, Lithium, Sodium, Potassium, Rubidium, Cesium and Francium. They are grouped together due to their identical electron configurations, containing only one valence electron. They also generally tend to lose their valence electron, forming a cation (with hydrogen being the exception). Alkali metals are malleable, ductile, highly reactive (thus not found freely in nature) and are known to conduct heat and electricity well. Due to these shared physical and chemical characteristics, these elements are grouped together. |
| 122. Electronegativity trend | |
| 123. Atomic Radius Trend | |
| 124. Ionization energy trend | |
| 125. Electron Affinity Trend | |
| 126. Metallic Character Trend | |
| 127. In the periodic table, elements that have similar properties are grouped in horizontal rows. True or False? | False |
| 128. Of the elements He, Fe, S, Ca, and K, the one that would react in a way that is most like Na is Ca. True or False? | True |
| 129. Which of the following elements is the largest in size? Question 7 options: A) O B) He C) K D) H | K |
| 130. With respect to their location on the periodic table, the elements having the greatest tendency to loose an electron are found Question 8 options: A) upper left B) lower left C) upper right D) lower right | Lower left (The most metallic elements are those having the greatest tendency to lose electrons e.g. Cesium is probably the most common metallic element.) |
| 131. As the atomic number increases within the alkali metal family, ionization energy Question 10 options: A) increases and atomic radius increases B) increases and atomic radius decreases C) decreases and atomic radius increases D) decreases and atomic radius decreases | Decreases and atomic radius increases |
| 132. Which of the following elements tends to hold onto its outer electrons most strongly? Question 11 options: A) He B) Na C) K D) Ne | He |
| 133. Briefly state the following trends: As the atomic number increases, ionization energy in a period | Increases |
| 134. Briefly state the following trends: As the atomic number increases, atomic radius in a period | Decreases |
| 135. Briefly state the following trends: As the atomic number increases, atomic radius in a family | Increases |
| 136. How do you determine which substances are least ionic? | The least ionic bond exists between the two atoms whose electronegativities are the closest to each other. That would occur between two atoms that are the closest to each other on the periodic table |
| 137. What is a lewis structure? | A Lewis structure is a symbol in which an atom's valence electrons are represented by dots placed around the element's symbol. |
| 138. What does a The Lewis structure of a compound show? What is used instead of using two dots for two electrons? | It shows how the valence electrons are arranged among the atoms in the molecule to show the connectivity of the atoms. Instead of using two dots to indicate the two electrons that comprise the covalent bond, a line is substituted for the two dots that represent the two electrons. |
| 139. Show the Lewis structure for water | Below is the Lewis structure for water. Two hydrogen atoms are each covalently bonded to the central oxygen atom. The bonding electrons are indicated by the dashes between the O and each H. The other two pairs of electrons that constitute oxygen's octet are called non-bonding electrons as they are not involved in a covalent bond. |
| 140. What are exceptions to the octet rule? | 1. molecules with an odd number of electrons 2. molecules in which an atom has less than an octet (usually in B and Be compounds) 3. molecules in which an atom has more than an octet. This is the largest class of exceptions and consists of molecules in which there are more than eight electrons in the valence shell of an atom, in elements such as P, S, As, and I. |
| 141. The Lewis structure for I2 is | False |
| 142. The Lewis structure for CH3OH is | True |
| 143. The Lewis structure for HCN is | False |
| 144. What do chemical formulas exist? What information do they provide chemists with? | They are a way to represent a molecule as a definite molecular unit (e.g. O2 or CO2) They provide chemist with the following information: - which elements are in the molecule - the exact number of atoms of each element that are in the molecule - an indication as to how the elements are bonded together |
| 145. What does an atom's valence indicate? | indicates the combining capacity of an element. It is either the charge on the ion or is the number of bonds formed by the atom. For example, calcium has two electrons in its valence shell and becomes an ion of charge positive two (and can form two single bonds as in CaF2). |
| 146. What is a binary compound? How do you name a binary compound? | A binary compound is a compound that has only two elements, such as MgO or CCl4. Binary compounds can form between metals and non-metals, hydrogen and other elements or between two 2 non-metals. Examples of binary compound categories are halides, oxides, sulphides. To name a binary compound, start with the name of the first element. Then add the name of the second element, replacing its ending with the suffix "ide". |
| 147. When writing and naming a binary compound, which element is written first? How many valence possibilities do single valence ions have? | The most electropositive element. Only one valence possibility. e.g. Group 1: Li+, Na+, K+, group 2: Be2+, Mg2+, groupd 15: N3- |
| 148. Give a few example of valence possibilities for multiple valence ions. | cobalt (Co2+, Co3+), copper (Cu+, Cu2+), lead (Pb2+, Pb4+), iron (Fe2+, Fe3+), nickel (Ni2+, Ni3+), tin (Sn2+, Sn4+) |
| 149. Fe2+ is... Fe2+ is called... Fe3+ is called... | iron (II) ferrous (For the ion with the lower charge, the suffix "ous" is added to the metal's name) ferric (For the ion with the higher charge, the suffix "ic" is added on to the metal's name.) |
| 150. The chemical FeO is made up of Fe2+ and O2- What is its name and old name? | Its name is iron (II) oxide. Its old name would be ferrous oxide. |
| 151. What are the general rules for writing binary compounds? | 1. Determine the ionic charges of the elements which are combining. 2. Choose a combination of the ions such that the sum of the ionic charges equals zero. 3. Write the symbol for the positive ion to the left and that for the negative ion to the right. Do not include the charges. 4. Use subscripts after each ion to indicate how many of each there is in the compound. |
| 152. What is a tip for binary compounds relating to subscripts? | The subscript for the cation is equal to the charge of the anion and the subscript for the anion is equal to the charge of the cation. So, the molecule formed between Al3+ and S2- is Al2S3, and is called aluminum sulphide. |
| 153. What is the chemical formula for the compound formed from Na and I? | NaI |
| 154. What is the chemical formula for the compound formed from zinc and bromine? | ZnBr2 |
| 155. What is the chemical formula for the compound formed from lead(IV) and oxygen? | PbO2 |
| 156. For binary covalent compounds (two non metal elements combining), the number of the most electronegative element is preceded by the Greek prefix corresponding to that number. Below is a list of these Greek prefixes. What are the prefixes from 1 to 10? | 1: mono, 2 : di, 3 : tri, 4 : tetra, 5 : penta, 6 : hexa, 7 : hepta, 8 : octa, 9 : nona, 10 : deca |
| 157. What is the valence of the element? What does the valence number refer to? | The capacity of the atoms of one element to combine with the atoms of another elements. The number of chemical bonds that an atom can form. |
| 158. Explain a fluorine atom becoming an anion. | For a flourine atom, the first shell contains 2 e-s and the outer shell contains 7 valence electrons, where it can hold up to 8. The valence shell is not full, there it is not stable. In order for the atom to be stable, it needs to add 1 more electron to its outer shell. If the flourine received one more electron, it would have 10 electrons and only 9 protons. This would make it an ion with a net charge of 1-. This is sometimes written as F- |
| 159. What is an ionic compound? How do we figure out how various atoms will combine to form ionic compounds? | When two charged ions are attracted to each other, combining to form an ion. By looking at the charge of the stable ions. e.g. aluminium chloride. The valence (for Al3+) means that aluminium will lose 3 electrons in order to become stable.ai |
| 160. What is the name of CuBr2? | copper (II) bromide |
| 161. What is the name of Al2O3? | aluminum oxide |
| 162. What is the name of RbCl? | rubidium chloride |
| 163. What is the name of N2O? | Dinitrogen oxide |
| 164. What is a binary acid and how do you name it? e.g. HCl | A binary acid contains hydrogen and one other non-metal hydro (prefix) + base name of non-metal + -ic (suffix) + acid e.g. HCl Hydrogen Chloride Hydro + Chloric + Acid Hydrochloric acid All acids donate hydrogen into solutions |
| 165. How do you name a ternary (3 elements) ionic compound? e.g. HClO3 | Drop the -ate and add -ic (mnemonic - somethimes tastes bad is ic) e.g. HClO3 Hydrogen Chlorate (-ate comes from O3) Chloric Acid (drop hydrogen and add acid at the end) All acids donate hydrogen into solutions |
| 166. How do you name a ternary (3 elements) ionic compound for HNO2 and H2SO3 | Hydrogen Nitrite (-ite comes from O2) Drop -ite and add -ous (mnemonic - light house) -> Nitrous Acid H2SO3 Hydrogen Sulfite -> Sulfurous Acid |
| 167. Are acids ionic? Why? | No, they are molecular The reason why they refer to ionic is because e.g. HCl has to dissociate into H+ + Cl- when dissolved in water. When dissolved in water, they become aqueous. H+(aq) + Cl-(aq) Which means they are surrounded by water molecules. |
| 168. What is a polyatomic ion? e.g. NH4(+), CO3(-2) | A group of atoms that has a net charge. (poly means many) E.g. Ammonium NH4+ # of protons = 11 # of electrons = 10 Net charge = +1 [NH4]+ -> polyatomic cation e.g. Carbonate CO3-2 # of protons = 30 # of electrons = 32 net charge = -2 [CO3]-2 -> poyatomic anion |
| 169. What is a polyatomic compound and what are the general rules for writing polyatomic compounds?? | A polyatomic compound is a substance that is made from more than 2 different elements e.g. BaSO4, NH4OH. 1. Determine the charges of the elements or groups of elements which are being combined. 2. Choose a combination of these elements or groups such that the sum of the charges equals zero. 3. Write the symbol for the positive ion to the left and that for the negative ion to the right. Do not include the charges. 4. Use subscripts after each ion to indicate the number present in the compound. Polyatomic ions require parentheses where there are more than one. The number 1 is understood and does not have to be written. In many cases, the subscript for the cation is equal to the charge of the anion and the subscript for the anion is equal to the charge of the cation. So, the molecule formed between Ba2+ and NO3- is Ba(NO3)2. But, make sure the subscripts are in lowest terms. |
| 170. What are oxyacids? | Oxyacids are acids that contain hydrogen, a non-metal and oxygen. Each of the oxyacids contains a radical which is bonded to a hydrogen ion. A radical is a group of non-metallic elements which are bonded together. They usually have a negative charge. Some examples are ClO3-, PO43-, SO42-. The table below contains the main oxyacids. |
| 171. What are derivative oxyacids? | The derivative oxyacids are oxyacids that have a different number of oxygen atoms than the main oxyacid. If one oxygen atom is removed from the main oxyacid, the suffix changes from "ic" to "ous". If two oxygen atoms are removed from the main oxyacid, the suffix changes from "ic" to "ous" and the prefix "hypo" is also added. If one oxygen atom is added to the main oxyacid, the prefix "per" is added. |
| 172. The main oxyacid containing H, Cl and O is HClO3 and is called chloric acid. What would be the name of the oxyacids with one oxygen atom is removed, two oxygen atoms are removed and one oxygen atom is added to the main oxyacid? | If one oxygen atom is removed, the formula becomes HClO2 and is called chlorous acid. If another oxygen atom is removed, the formula becomes HClO and it is named hypochlorous acid. On the other hand, if an oxygen atom is added to the main oxyacid, the formula becomes HClO4 and it is called perchloric acid. |
| 173. What is the name of H2CO3? hypocarbonous acid carbonous acid carbonic acid percarbonic acid | Carbonic acid |
| 174. HClO2 is called hypochlorous acid. True or false. | False (chlorous acid) |
| 175. What is the chemical formula of persulphuric acid? HSO3 H2SO3 H2SO4 H2SO5 | H2SO5 |
| 176. Hypophosphorous acid is: H3PO H3PO2 H3PO3 H3PO4 H3PO5 | H3PO2 |
| 177. When the hydrogen from an acid is replaced by a metallic element, a salt is formed. What are the rules for naming salts formed from oxyacids? e.g. nitric acid (HNO3) | For the salt formed from the main ("ic") oxyacid, the suffix changes from "ic" to "ate", the word "acid" is omitted and the name of the metal is placed in front of the anion's name. For the salt formed from the "ous" oxyacid, the suffix changes from "ous" to "ite", the word "acid" is omitted and the name of the metal is placed in front of the anion's name. For the salt formed from the "hypo"..."ous" oxyacid, the suffix changes from "ous" to "ite", the prefix hypo is added, the word "acid" is omitted and the name of the metal is placed in front of the anion's name. For the salt formed from the "per" oxyacid, the suffix changes from "ic" to "ate", the word "acid" is omitted and the name of the metal is placed in front of the anion's name. The sodium salts derived from nitric acid (HNO3) are: NaNO and is named sodium hyponitrite NaNO2 and is named sodium nitrite NaNO3 and is named sodium nitrate NaNO4 and is named sodium pernitrate |
| 178. What is the chemical formula for chromium (II) bicarbonate? | Cr(HCO3)2 |
| 179. What is the chemical formula for lithium hypochlorite? | LiClO |
| 180. What is the chemical formula for sodium hydroxide? | NaOH |
| 181. What is the name of CuSO4? | copper (II) sulphate |
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