group 2, group 7 and ions tests

Question 1

what are group 2 elements called?

Answer 1

Alkaline earth metals

Question 2

what does ‘alkaline in alkaline earth metals mean?

Answer 2

the oxides of these metals releases OH- ions in solution

Question 3

what does ‘earth’ in alkaline earth metals mean?

Answer 3

Very abundant in the earths crust

Question 4

what structure do all gorup 2 elements have?

Answer 4

All Group 2 metals have the giant metallic lattice structure

Question 5

how do group 2 metals conduct electricity?

Answer 5

Metals conduct electricity when solid or liquid because the electrons are delocalised and can move

Question 6

why do group 2 metals have High Melting and Boiling Points

Answer 6

It takes a lot of energy to break the strong electrostatic attraction between the ions and the delocalised electrons

Question 7

give the general equation for metals + oxygen

Answer 7

2M(s) + O2(g) —–> 2MO(s)

Question 8

give the general equation for metals + water

Answer 8

M(s) + 2H2O(l) —> M(OH)2(s) + H2(g)

Question 9

give the general equation for metals + steam

Answer 9

M(s) + H2O(g) —–> MgO(s) + H2(g)

Question 10

give the general equation for metals + an acid (use H2SO4)

Answer 10

M + H2SO4 —-> MSO4 + H2

Question 11

What is the reactivity of metals like down a group?

Answer 11

More Reactive Down the Group

Question 12

What do metals get more reactive down the group/why does ionisation energy decrease down the group?

Answer 12

1. There are more shells of electrons.
2. Therefore, the outer electrons are further from the nucleus and more shielded.
3. So the nuclear attraction for the outer electron is less.
4. The outer electrons are more easily lost.

Question 13

What is a common use for calcium oxide/hydroxide?

Answer 13

Neutralisation of acidic soils

Question 14

what is a common ise for magnesium hydroxide or calcium carbonate?

Answer 14

Neutralises stomach acids when you have a stomach ache

Question 15

What is produced when a metal oxide reacts with water?

Answer 15

metal hydroxide is only produced

Question 16

what occurs to the pH of hydroxides down the group?

Answer 16

increases

Question 17

ACID + BASE —–>

Answer 17

SALT + WATER

Question 18

ACID + CARBONATE ——>

Answer 18

SALT + WATER + CARBON DIOXIDE

Question 19

Do group 2 loose or gain electrons, if so are they oxidised or reduced, if so are they reducing agents or oxidising agents?

Answer 19

loose electrons
oxidised
reducing agents

Question 20

what are the name of the group 7 elements?

Answer 20

Halogens

Question 21

what is the structure of the group 7 elements, and what are the bonds and forces present?

Answer 21

simple molecular lattice, covalent bonds, london forces

Question 22

what type of molecules are the halogens?

Answer 22

diatomic

Question 23

how are covalent bonds described?

Answer 23

short and strong

Question 24

how are london forces described?

Answer 24

long and weak

Question 25

what state are F2, Cl2, Br2, and I2?

Answer 25

F2, Cl2 = gas Br2 = liquid I2 = solid

Question 26

describe and explain the mp and bp of the halogens

Answer 26

The boiling points and melting points of the halogens increase as you go down the group: The molecules have more electrons. So the London forces between the molecules are stronger. Therefore, more energy is needed to break them.

Question 27

what is the half equation for flourine?

Answer 27

F2 + 2e- → 2F-

Question 28

describe and explain the reactivty of the halogens

Answer 28

Reactivity decreases down Group 7: Halogen atoms get larger with more shells of electron More inner shells shield incoming electrons more from the nucleus Incoming electrons don’t get as close to the nucleus So the attraction for incoming electrons is weaker So ions form less easily

Question 29

what is a disproportionation reactions?

Answer 29

The simultaneous oxidation and reduction of the same species

Question 30

good use of chlorine

Answer 30

Chlorine kills bacteria (Sterilisation)

Question 31

Why do some people not want the water to be chlorinated?

Answer 31

chlorine is toxic

Question 32

chlorine disproportionation

Answer 32

Cl2 + H2O HCl + HOCl

Question 33

how does a displacement reaction work?

Answer 33

the more reactive reactiant replaces the less reactive one

Question 34

colour of iodine in cyclohexane

Answer 34

pink/purple/violet

Question 35

colour of bromine in cyclohexane

Answer 35

orange

Question 36

How to test for halogens

Answer 36

1. add silver nitrate solution to see a precipitate | 2. add dilute ammonia, and then conc ammonia to see the precipitate dissolve

Question 37

Chloride ion with silver nitrate

Answer 37

A white precipitate in silver nitrate | This dissolves in dilute ammonia and conc ammonia

Question 38

Bromide ion with silver nitrate

Answer 38

A cream precipitate in silver nitrate | This doesn't dissolves in dilute ammonia, but will in conc ammonia

Question 39

Iodide ion with silver nitrate

Answer 39

A yellow precipitate in silver nitrate | This doesn't dissolve in any ammonia at all, no matter how hot or concentrated

Question 40

what is the test for a carbonate, and how can you prove it is a carbonate?

Answer 40

Add dilute acid (normally nitric acid), there should be effervecence/fizzing bubble through limewater, and a white ppt should form (turns the lime water white/cloudy)

Question 41

what is the test for a sulfate?

Answer 41

add barium nitrate, a white ppt should form

Question 42

what is the correct order for the ion tests?

Answer 42

1. carbonate 2. sulfate 3. halide

Question 43

why carbonate first?

Answer 43

sulfate nor halide ions produce a gas with a dilute acid, therfore if no bubble are produced then you can carry on

Question 44

why sulfate second?

Answer 44

baso4 is white and insolube. barium carbonate is also white

Question 45

test for ammonium ions

Answer 45

boil in dilute sodium hydoxide, and test with damp rest litmus, the gas produced should turn the red litmus blue