Group 2 + 7 (P1+P3)

Question 1

What happens to the atomic radius, melting point, ionisation energy and reactivity in group 2?

Answer 1

Atomic radius - increases going down
melting point - decreases going down
ionisation energy - decreases going down
reactivity - increases going down

Question 2

Hydroxides and sulfates (solubility)

Answer 2

for HYDROXIDES Mg(OH)2 and going down solubility INCREASES
for SULFATES MgSO4 and going down solubility DECREASES

Question 3

Use of Mg(OH)2

Answer 3

medicine/indigestion

Question 4

Use of Ca(OH)2

Answer 4

Agriculture

Question 5

Use of BaSO4

Answer 5

good for absorbing X - rays.

Question 6

Testing for SO42- ions

Answer 6

Add BaCl2
White ppt if ions present

Question 7

What happens to the electronegativity, melting and boiling points in group 7?

Answer 7

electronegativity - decreases going down
melting and boiling points - increases going down

Question 8

Halogens act as…

Answer 8

oxidising agents
F- (strongest) to I- (weakest)

Question 9

Halide ions act as…

Answer 9

reducing agents
I- (strongest) to F- (weakest)

Question 10

Test for Cl-

Answer 10

AgNO3
White ppt

Question 11

Test for Br-

Answer 11

AgNO3
Cream ppt

Question 11

Test for I-

Answer 11

AgNO3
Yellow ppt

Question 12

Test for AgCl

Answer 12

Dilute NH3
White ppt dissolves

Question 13

Test for AgBr

Answer 13

Conc NH3
Cream ppt dissolves
With dilute NH3 cream ppt remains

Question 14

Uses of chlorine in water

Answer 14

DISPROPRTIONATION REACTION
Cl2(g) + H2O(l) <–> HClO(aq) + HCl(aq)
treats water, in swimming pool
HClO is an oxidising agent used in bleach