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Description
Flashcards by Layla Ahmed, updated more than 1 year ago
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Created by Layla Ahmed
about 8 years ago
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| Question | Answer |
| What is Atomic Theory? | The theory that all matter is made up of atoms. Atoms of each element are effectively identical, but differ from those of other elements, and unite to form compounds in fixed proportions. |
| Explain how Atomic Size changes and why. | Atomic size decreases from left to right due to the pull of the positive nucleus around the electrons. It increases going down 'cause of the added valence shell. |
| What is Atomic Size? | The length btwn the middle of nucleus and the last valence shell. |
| What is electronegativity? | Electronegativity is essentially how much an atom pulls other electrons towards itself. |
| Explain the EN trend. | EN goes up as you go left to right because of the protons increasing and pulling the electrons towards itself. It goes down when you go down because of the electrons shielding the outer ones from the pull. |
| What is ionization energy? | The energy required to take an electron out of the atom. |
| Explain the IE trend. | IE goes up as you go left to right 'cause electrons with more valence electrons want to keep their electrons. It goes down as you go down because the the outer electrons have less pull on them due to electron shielding so it's easier to take out. |
| What is electron affinity? | The change in energy (in kJ/mole) of a neutral atom (in the gaseous phase) when an electron is added to the atom to form a negative ion. In other words, the neutral atom's likelihood of gaining an electron. |
| Explain the EA trend. | EA goes up as you go left to right due to the positive pull (the stronger the attraction, the higher the energy released). It goes down as you go down due to electron shielding, which takes down the attraction btwn the nucleus and incoming electron. |
| What is VSEPR theory? | Valence Shell Electron Pair Repulsion theory. |
| When is an atom tetrahedral? | Central atom w/ 4 bonding pairs, no lone pairs |
| When is an atom Planar Triangular? | Central atom has an incomplete octet |
| What atom is linear? | Central atom w/4 bonding pairs and lone pairs on the non-central atom |
| When is an atom bent? | Central atom w/ 2 bonding pairs and 2 lone pairs |
| When is an atom a Trigonal Pyramid? | Central atom w/ 1 lone pair and 3 bonding pairs |
| Which shapes are polar molecules? Which shapes are not? What is the exception? | Tetrahedral & Linear molecules are non-polar, everything else is polar. The exception for polar is when the formula has more than 2 different elements. |
| How do you find the polarity of a bond? Molecule? | To find the polarity of a bond: 1. Subtract the central atom & the other atom’s EN 2. If the answer is: 0-0.5= NON POLAR COVALENT, 0.5-1.7 OR 1.9= POLAR COVALENT, 1.9-3.3= IONIC Remember to say it’s a BOND To find the polarity of the molecule: 1. Put a sigma +/- beside the corresponding element. 2. Put arrows going from positive to negative. See if they cancel out. 3. If you don’t get it (and you won't) just look at the chart above. |
| How do you use a Lewis diagram in IONIC bonds? | Ex: Na + Cl = [Na]+ [Cl]- Remember to add dots around the Na and Cl and give Cl a full octet. |
| How to make a Lewis diagram in COVALENT bonds? | This....is a freaking guessing game sometimes I swear to God. But use sticks to show bonds. |
| What is a Chemical Change? | Changes that alter the composition of matter. EX Wood burning, Bread baking, etc. |
| What is a Physical Change? | Changes that affect the physical appearance of matter, but not its composition. Ex. Evaporation, Melting, Boiling |
| Dalton's Atomic Theory? | 1) All matter is composed of extremely small particles called atoms, which cannot be subdivided, created, or destroyed. 2) Atoms of a given element are identical in their physical and chemical properties. 3) Atoms of different elements differ in their physical and chemical properties. 4) Atoms of different elements combine in simple. whole-number ratios to form compounds 5) In chemical reactions, atoms are combined, separated, or rearranged but never created, destroyed, or changed. |
| Classify Matter | Two Types of Matter: 1. Pure (i.e Elements & Compounds) 2. Mixture (i.e Solutions & Heterogeneous) |
| What is the weight of a subatomic particle? | Proton & Neutron: 1.67 x 10(-24) Electron: 9.02 x 10(-28) |
| SI Base Units of: 1. Weight 2. Length 3. Time | 1. Kg (Kilogram) 2. m (Metre) 3. S (Second) |
| What is J.J Thomson's Plum Pudding? | He weighted an electron using a cathode ray tube and proved that electrons existed and were electric. In this model, the atom was made up of negatively charged electrons (the plums) surrounded by a sphere of positively charged fluid (the pudding). |
| Explain Rutherford's Gold Foil Experiment. | He proved that there were protons in the nucleus. He sent an Alpha ray through a gold foil. Usually it goes straight through but the ones that hit the nucleus throw off. |
| Standard Chemical Notation? | |
| What is Periodic Law? | Chemical and Physical properties of elements repeat in a regular, periodic patter when they are arranged according to their atomic matter. |
| What is Effective Nuclear Charge? | Overall positive force exhibited by protons in a nucleus acting on each electron. |
| What is the shielding effect? | The dampening of the effective nuclear charge by the negative charge of the electron in inner shells. |
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