ES - P Block Elements

Question 1

what group are the halogens?

Answer 1

group 7

Question 2

how many electrons are in the outer shell of all halogens?

Answer 2

7 (as in group 7)

Question 3

what do the halogens occur as?

Answer 3

diatomic molecules e.g Cl2, Br2, F2

Question 4

why are group 7 elements the most reactive non-metals (how do they become stable)?

Answer 4

due to having 7 e- in their outermost shell they will easily attract another from a metal atom forming a halide ion in an ionic compound

Question 5

properties demonstrated by group 7 down the group:

Answer 5

become less reactive (F2 most reactive)
become darker in colour
melting and boiling point increase
hang from gases to liquid to solids at RTP
become less volatile
(there’s no trend for solubility)

Question 6

why does reactivity decrease down group 7?

Answer 6

because the size of the molecules get bigger reducing the attraction between the core and outer shell of 7+ decreases
this means that fluorine is the strongest oxidising agent

Question 7

why are half equations useful?

Answer 7

show more clearly what happens in a redox reaction (both oxidation and reduction occur)

Question 8

what happens when a halide ion reacts with silver ions?

Answer 8

a precipitate is formed when silver ion is added to chloride (white), bromide (cream), iodide (yellow)
Ag+(aq) + X- (aq) —-> AgX(s)

colour changes occur (above) but can be hard to distinguish between so sometimes ammonia solution is added