C4-Chemistry

Frage	Antworten
the ..... of attraction between molecules are weak	intermolecular forces
this results in them having ..	low melting points
they also do not ....	conduct electricity
because...	they do not have any free electrons
the group one elements are also known as the	the alkali metals
alkali metals are stored under oil because...	they are very reactive with air and water
in a flame test lithium goes..	RED
sodium goes..	YELLOW
and potassium goes..	PURPLE
whats the formula for the reaction with alkali metals and water?	alkali metal+water-->alkali metal hydroxide+hydrogen
what is the balanced symbol equation for this?	2(AM)+2H2O--->2(AM)OH+H2
the melting point and boiling point of the alkali metals ...... going down the group	decrease
the density ..... going down the group	increases
what happens when a group 1 element reacts?	the atom looses 1 electron to form a positive ion with a stable electronic structure
why do the alkali metals become more reactive as you go down the group?	because the outer shell gets further away from the nucleus making it easier for the atom to lose an electron
what is oxidation?	the loss of electron from an atom
what is another word used for the group 7 elements?	The halogens
at room temperature chlorine is a	green gas
bromine is an	orange liquid
iodine is a	grey solid
what is iodine used as?	an antiseptic to sterilise wounds
what is chlorine used for?	sterilising water and to make pesticides and plastics
when group 1 and group 7 elements react the formula is	group 1 element+group 7 element ----> group 1 element group 7 element with 'ide' on the end
as we go down the group the halogens become ... reactive	less
and their melting and boiling points ...	decrease
a more reactive halogen.... a less reactive halogen	displaces
whats the formula for reacting 2 group 7 elements together?	potassium bromide +chlorine ----> potassium chlorine + Bromine
what happens when a group 7 element reacts?	it gains one electron to form a negative ion with a stable electronic structure
what is reduction?	the gain of electrons
the halogens become less reactive as you go down the group because..	the outer shell gets further away from the nucleus meaning it's harder for the atom to gain an electron
what's an easy way to remember oxidation and reduction?	OILRIG Oxidation Is Loss of electrons Reduction Is Gain of electrons
in transition metals copper compounds are...	BLUE
iron compounds are ..	GREY/GREEN
iron compound(III) are	ORANGE/BROWN
many transition metals and their compounds can be used as	catalysts
give 2 examples of when transition metals are used as catalysts?	1.iron is used in the haber process 2.nickel is used in the manufacturing of margarine
what is thermal decomposition?	a reaction where a substance is broken into similar substances by heating
what is the reaction between a transition metal ion and sodium hydroxide solution called?	a precipitate reaction
what can iron be used for?	to make steel which is used to make cars and grinders because it is very strong
what is copper used for?	to make electrical wiring as it is a good conductor. it was also used to make brass
give 5 properties of metals.	1.lustrous eg gold(jewellery) 2.hard (high density) 3.High tensile strength 4.High melting and boiling points 5. Good conductors of heat and electricity
what type of bonds do metals have?	strong metallic bonds
how are these metalic bonds formed?	metal atoms packed so close together that the outer electron shells overlap and form the bond
how are metals able to conduct electricity?	because the atoms are very close together and the electrons can move from atom to atom
what is a superconductor?	a metal at a very low temperature which has very little resistance
what do scientists want to find?	a superconductor that will work at room temperature as very low temps are costly to maintain and impractical for large scale uses
what are the 4 main sources of water?	reservoirs 2.lakes 3.rivers 4.aquifiers
name 4 things water can contain before it is treated and purified?	1.insoluble particles 2.pollutants 3.microbes 4.dissolved salts and minerals
what charge do electrons have?	negative charge
what charge to protons have?	positive charge
what charge do neutrons have?	neutral charge
what are the 3 main stages of the water treatment process?	sedimentation 2.filtration 3.chlorination
what is an isotope?	when a element has the same number of protons but a different number of neutrons
what is the atomic number?	the number of protons and the number of electrons an element has
what is the mass number?	the number of protons and neutrons added together
what is an element?	a substance that cannot be broken down chemically and contains only one type of atom
what is a compound?	a substance that contains at least two elements that are chemically combined
what is the electronic structure of what electrons occupy which each shell in an atom?	2, 8, 8
the groups along the top determine	how many electrons the atom has on it's outer shell
the groups down the side determine	the amount of shells the atom has
the right hand side of the periodic table is the...	non metals
the left hand side of the periodic table is the..	metals
the middle of the periodic table is the...	transition elements
an ionic bond is...	a bond between a metal and a non metal
why are we prevented from distiling our water?	because it takes a lot of energy and the costs are too high
in an ionic bond the electrons..	transfer
a covalent bond is a bond between..	2 non metals
in a covalent bond the electrons are...	shared
group 1 elements reactivity goes .... as you go down the periodic table	UP
give 3 examples of pollutants that may be found in water.	1.nitrates from run off fertilisers 2.lead for old pipes and plumbing 3.pesticides from crop spraying

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