gcse aqa chemistry topic 1 Flashcards
(24 cards)
define element,compound and mixture
an element is one/specific type of atom,
a compound is two or more elements chemically bonded together
a mixture is when different elements or compounds are together but aren’t chemically bonded.
what are the subatomic particles of an atom?
the atom includes the proton,neutron and electron
the proton carries a positive charge,the electron carries a negative charge and the neutron has no charge
define isotope
an isotope is a different version of an element with a different amount of neutrons
what is the atomic mass of an element?
the atomic mass is the amount of protons and neutrons
what does the period of an element tell you?
the amount of shells an element has
what does the group number of an element tell you?
the amount of electrons on the outer shell
who was mendeelev and what did he do?
he was a Russian scientist and he left gaps in the periodic table because he predicted that there were unknown elements due to experiments he carried out.
what did bohr do?
bohr was a scientist and he proved that the plum pudding model was wrong because of the the fact that the proton and electrons would be attracted together. he came up with the nuclear model which showed electrons orbitting the nucleus at energy levels.
before subatomic particles were discovered,what were the elements ordered in?
their actual mass.
what are the group 1 metals called?
the alkali metals
what happens when group 1 react with water?
the produce hydroxides and an alkaline solution is formed
describe the trends in group 1 as you go down
boiling/melting points decrease
reactivity increases
relative atomic mass increase
are group 1 metals hard or soft?
soft
why are they stored under oil?
to prevent them from reacting with air
what do group 1 metals form when they react with chlorine?
they form salts in the name of chloride.
what are the group 7 elements called?
they are called the halogens
iodine goes straight from a gas to a solid, what is this called?
sublimation.
what is chlorine?
a green poisonous gas
what is fluorine?
a green poisonous gas
describe the trends as you go down group 7
boiling/melting points increase
reactivity decreases
relative atomic mass increases
whats the most reactive group 7 element and why?
fluorine because it has the least shells meaning it can gain an electron very easily because the attraction between the gained electron and the nucleus is strong.
what are the nobles gases and why are the not reactive?
the noble gases are gases which have a full outer electronic shell,this means they are not reactive because they don’t need to gain or lose electrons as its outer energy level is full
describe the qualities of transition metals
they are good conductors of heat and electricity
they are strong and dense
high melting and boiling points
compare group 1 and the transition metals
group 1 is more reactive
transition metals are stronger,group 1 is softer
transition metals have higher boiling points
transition metals can conduct electricity whereas group 1 cannot.
