gcse aqa chemistry topic 1

Question 1

define element,compound and mixture

Answer 1

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.

Question 2

what are the subatomic particles of an atom?

Answer 2

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

Question 3

define isotope

Answer 3

an isotope is a different version of an element with a different amount of neutrons

Question 4

what is the atomic mass of an element?

Answer 4

the atomic mass is the amount of protons and neutrons

Question 5

what does the period of an element tell you?

Answer 5

the amount of shells an element has

Question 6

what does the group number of an element tell you?

Answer 6

the amount of electrons on the outer shell

Question 7

who was mendeelev and what did he do?

Answer 7

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.

Question 8

what did bohr do?

Answer 8

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.

Question 9

before subatomic particles were discovered,what were the elements ordered in?

Answer 9

their actual mass.

Question 10

what are the group 1 metals called?

Answer 10

the alkali metals

Question 11

what happens when group 1 react with water?

Answer 11

the produce hydroxides and an alkaline solution is formed

Question 12

describe the trends in group 1 as you go down

Answer 12

boiling/melting points decrease
reactivity increases
relative atomic mass increase

Question 13

are group 1 metals hard or soft?

Answer 13

soft

Question 14

why are they stored under oil?

Answer 14

to prevent them from reacting with air

Question 15

what do group 1 metals form when they react with chlorine?

Answer 15

they form salts in the name of chloride.

Question 16

what are the group 7 elements called?

Answer 16

they are called the halogens

Question 17

iodine goes straight from a gas to a solid, what is this called?

Answer 17

sublimation.

Question 18

what is chlorine?

Answer 18

a green poisonous gas

Question 19

what is fluorine?

Answer 19

a green poisonous gas

Question 20

describe the trends as you go down group 7

Answer 20

boiling/melting points increase
reactivity decreases
relative atomic mass increases

Question 21

whats the most reactive group 7 element and why?

Answer 21

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.

Question 22

what are the nobles gases and why are the not reactive?

Answer 22

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

Question 23

describe the qualities of transition metals

Answer 23

they are good conductors of heat and electricity
they are strong and dense
high melting and boiling points

Question 24

compare group 1 and the transition metals

Answer 24

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.