The halogens (Gr 7) - ES

Question 1

What does fluorine look like at room temp

Answer 1

colourless gas

Question 2

What does chlorine look like at room temp

Answer 2

pale green gas

Question 3

What does bromine look like at room temp

Answer 3

brown/red liquid

Question 4

What does iodine look like at room temp

Answer 4

silver/black solid

Question 5

What trends happens down the halogens

Answer 5

colour gets darker, melting point and boiling point increase : they are less volatile and switch from gas to liquid to solid as intermolecular bonds get stronger

Question 6

Halogens solublity

Answer 6

they are not very soluble in water but much mores soluble in organic solvents

Question 7

Halogens as elements characteristics

Answer 7

they exist as diamotic molecules, they are in the p-block on the periodic table and outer shell for all is s²p⁵

Question 8

Chemical properties of halogens

Answer 8

to achieve noble gas configuration a halogen atoms has to gain one electrons which means they are oxidising agents. Oxidising power increases going up the group

Question 9

How is oxidising power affects up the group of halogens

Answer 9

it increases because the incoming electron is closer and less shielded from the positive nucleus so attraction is stronger

Question 10

Halogens with metals

Answer 10

the halogens form an ionic compound. They fully gain an extra electron, becoming halide ions

Question 11

Halogens with non-metals

Answer 11

the halogens share electrons, forming a covalent bond

Question 12

Cl⁻ colour

Answer 12

colourless

Question 13

Br⁻ colour

Answer 13

colourless

Question 14

I⁻ colour

Answer 14

colourless

Question 15

Cl₂ in aqueous solution colour

Answer 15

very pale green

Question 16

Br₂ in aqueous solution colour

Answer 16

orange

Question 17

I₂ in aqueous solution colour

Answer 17

brown

Question 18

Cl₂ in organic solvents colour

Answer 18

pale green

Question 19

Br₂ in organic solvents colour

Answer 19

brown

Question 20

I₂ in organic solvents colour

Answer 20

purple

Question 21

A halogen higher in the group is ale to …

Answer 21

oxidise (react with) the halide ion of a halogen lower in the group

Question 22

How to see clearly the colour difference in halogens

Answer 22

an organic solvent is added and the mixture is shaken, the organic solvent and water do not mic so 2 layers form. Halogen molecules are non-polar so dissolve better in the upper, organic layer (also non-polar) giving it a characteristic colour which is more distinctive to see

Question 23

Tests for halides in solution

Answer 23

add silver nitrate (AgNO) and then to check shake with aqueous ammonia solution

Question 24

Fl⁻ and AgNO observation + formula + ionic equation

Answer 24

no precipitate

Question 25

Cl⁻ and AgNO observation + formula + ionic equation

Answer 25

white precipitation, AgCl (silver chloride) Ag⁺ + Cl⁻ -> AgCl

Question 26

Br⁻ and AgNO observation + formula + ionic equation

Answer 26

cream precipitation, AgBr (silver bromide) Ag⁺ + Br⁻ -> AgBr

Question 27

I⁻ and AgNO observation + formula + ionic equation

Answer 27

yellow precipitation, AgI (silver iodide) Ag⁺ + I⁻ -> AgI

Question 28

What happens to silver halides when left in the sun

Answer 28

they start to go grey/black due to formation of silver as they are light sensitive

Question 29

What happens when AgCl is shaken with aqueous ammonia solution

Answer 29

completely redissolves

Question 30

What happens when AgBr is shaken with aqueous ammonia solution

Answer 30

partially redissolves

Question 31

What happens when AgI is shaken with aqueous ammonia solution

Answer 31

does not redissolve

Question 32

Risks of using chlorine

Answer 32

very toxic and any leak can be dangerous as it is a gas so will spread quickly

Question 33

Uses of chlorine

Answer 33

water treatment (drinking and pools) to kill germs, make household bleach, extract bromine from sea water, make HCl