Topic 4 - Inorganic Chemistry

Question 1

State and explain the trend in ionisation energy down group 2 of the periodic table

Answer 1

The first I.E decreases down the group, due to the increased level of shielding as the number of electron shells between the nucleus and the outermost electron(s) increases, with the level of e-e repulsion, making it easier for an electron to be pulled away.

Question 2

State and explain the trend in reactivity down group 2 of the periodic table

Answer 2

The reactivity increases down the group, due to the increased level of shielding as the number of electron shells between the nucleus and the outermost electron(s) increases with the level of e-e repulsion, making it easier for an electron to be pulled away.

Question 3

Give the general reaction of group 2 hydroxides with acids

Answer 3

X(OH)2 + 2HCl –> 2H2O + MgCl2

Question 4

Describe the trend in thermal stability in group 1 and 2 nitrates

Answer 4

Group 2 nitrates all show signs of greater thermal decomposition, and all but lithium in group 1 show signs of lesser thermal decomposition.

Question 5

Describe the trend in thermal stability in group 1 and 2 carbonates

Answer 5

Group 2 carbonates all show signs of decomposition, but all but lithium show no signs of thermal decomposition at all

Question 6

What colour flame does the lithium ion produce when burnt?

Answer 6

Red

Question 7

What colour flame does the sodium ion produce when burnt?

Answer 7

Yellow/Orange

Question 8

What colour flame does the Potassium ion produce when burnt?

Answer 8

Lilac

Question 9

What colour flame does the rubidium ion produce when burnt?

Answer 9

Red/Purple

Question 10

What colour flame does the caesium ion produce when burnt?

Answer 10

Blue/Violet

Question 11

What colour flame does the beryllium ion produce when burnt?

Answer 11

No colour

Question 12

What colour flame does the magnesium ion produce when burnt?

Answer 12

No colour

Question 13

What colour flame does the calcium ion produce when burnt?

Answer 13

Brick Red

Question 14

What colour flame does the strontium ion produce when burnt?

Answer 14

Crimson Red

Question 15

What colour flame does the barium ion produce when burnt?

Answer 15

Apple Green

Question 16

What causes the coloured flames produced by group 1 and 2 elements?

Answer 16

The excitement of electrons from their ground state to a higher energy level during a flame test, followed by its immediate return to its original level, releasing energy of a particular visible wavelength

Question 17

Describe and explain the trend in melting and boiling temperature down group 7

Answer 17

The melting and boiling temperatures increase down the group as the strength of the London Forces present increase with the number of electrons, and the size of the electron cloud

Question 18

Name the salts, all common forms of which are soluble

Answer 18

Sodium, Potassium and Ammonium salts, and Nitrate salts

Question 19

Which Chlorides are insoluble?

Answer 19

Silver and Lead Chloride

Question 20

Which Sulphates are insoluble?

Answer 20

Lead, Barium and Calcium Sulphate

Question 21

Which Carbonates are soluble?

Answer 21

Sodium, Potassium and Ammonium Carbonate

Question 22

Which Hydroxides are soluble?

Answer 22

Sodium, Potassium and Ammonium Hydroxide

Question 23

Describe and explain the trend in reactivity down group 7

Answer 23

Group 7 elements decrease in reactivity down the group as their electronegativity decreases, meaning their ability to attract another electron into its outermost shell