halogens

Question 1

trend in boiling and melting points of halogens

Answer 1

Mp, BP increase down the group as the London forces increase due to increased dipole dipole interactions from an increase in electrons

Question 2

volatility

Answer 2

how easy turn into gas - volatile known to have a low mp.

Question 3

outer shell configuration and ion formed in redox reactions

Answer 3

s2, p5 and 1-

Question 4

How are halogens oxidising agents

Answer 4

react by gaining an electron to form 1- ion so reduced. In this process another element is oxidised and they lose that electron given to the halogen and therefore they are said to be ‘oxidising agents’

Question 5

trend in reactivity of group 7

Answer 5

• atomic radii increases
• shielding increases (overrides nuclear charge)
  -harder for nucleus to attract outer electron as less nuclear attraction. (electron affinity decreases)
• reactivity decreases

Question 6

Cl2 water colour change when reacted w KCL

Answer 6

no reaction in both aq and organic KCL solution

Question 7

CL2 water colour change when reacted with KBR

Answer 7

colourless to …
- orange (aq)
- brown organic layer

Question 8

Cl2 water colour change when reacted with KI

Answer 8

colourless to …
- chlorine orange/ brown (aq)
- or purple organic layer

Question 9

Bromine colour change with KCL, KI and KBR

Answer 9

• remains yellow in aq solution and orange in organic layer w KCL, KBR
• in KI yellow to orange/ brown(aq) or purple (OL)

Question 10

Iodine colour change with KCL, KI and KBr

Answer 10

remains orange/ brown in aqueous solution and purple in organic layer for all reactions

Question 11

what are halides

Answer 11

anions formed when a halogen gains an electron

Question 12

general ionic equation for displacement reactions

Answer 12

X2 + 2Y- —> 2X- + Y2

halide ion and halogen give different halide ion and different halogen

Question 13

oxidising agents

Answer 13

halogen molecules

Question 14

reducing agents

Answer 14

halide ions