PMT Group 1 and 2

Question 1

What is a common name

given to group 2 metals?

Answer 1

Alkaline earth metals

Question 2

What is the most reactive

metal of group 2?

Answer 2

Barium

Question 3

List 3 physical properties of

group 2 metals

Answer 3

● High melting and boiling points
● Low density metals
● Form colourless (white) compounds

Question 4

The highest energy electrons
of group 2 metals are in which
subshell?

Answer 4

S subshell

Question 5

Does reactivity increase or
decrease down group 2?
Why?

Answer 5

● Increases
● Electrons are lost more easily because larger
atomic radius and more shielding.

Question 6

What happens to the first
ionisation energy as you go
down group 2? Why?

Answer 6

Decreases because:
-Number of filled electron shells increases down the group →
increased shielding
- Increased atomic radius → weaker force between outer - -
-Electron and nucleus → less energy needed to remove
electron

Question 7

What type of reaction is the
reaction between group 2
elements and oxygen?

Answer 7

Redox reaction

Question 8

Write an equation for the
reaction of calcium and
oxygen

Answer 8

2Ca (s) + O2 (g) → 2CaO (s)

Question 9

What are the products when
group 2 elements react with
water?

Answer 9

Hydroxide and hydrogen gas

Question 10

Which group 2 element

doesn’t react with water?

Answer 10

Beryllium

Question 11

Which group 2 element reacts

very slowly with water?

Answer 11

Magnesium

Question 12

What type of reaction is the
reaction between group 2
metal and water?

Answer 12

Redox reaction

Question 13

Write an equation for the
reaction of barium and
water

Answer 13

Ba (s) + 2H2O (l) → Ba(OH)₂ (aq) + H₂ (g)

Question 14

What is oxidised and what is
reduced in a reaction between
group 2 metal and water?

Answer 14

Metal → oxidised
One hydrogen atom from each water →
reduced

Question 15

What are the products when a
group 2 oxide reacts with an
dilute acid?

Answer 15

Salt and water

Question 16

Write an equation for the
reaction of calcium oxide
and hydrochloric acid

Answer 16

CaO (s) + 2HCl (aq) → CaCl2
(s) + H₂O
(l)

Question 17

What is formed when group 2

oxides react with water?

Answer 17

Metal hydroxide

Question 18

Write an equation for the
reaction between a group 2
oxide and water

Answer 18

MO (s) + H2O (l) → M(OH)2

(aq)

Question 19

What group 2 metal oxide is

insoluble in water?

Answer 19

Beryllium oxide

Question 20

Write an equation for the
reaction between Mg(OH)2
and nitric acid

Answer 20

2HNO3 (aq) + Mg(OH)2 (aq) Mg(NO3)2(aq) + 2H2O (l)

Question 21

What is the trend in hydroxide

solubility down group 2?

Answer 21

Increases down the group
Mg(OH)₂ is slightly soluble
Ba(OH)₂ creates a strong alkaline solution

Question 22

What is the trend in sulphate

solubility down group 2?

Answer 22

Group 2 sulphates become less soluble
down the group with BaSO4 being the
least soluble.

Question 23

Explain the reasons for the
trend of thermal stability in
group 1 and 2 carbonates

Answer 23

Group 2 carbonates are more thermally stable as you go down the group this is because the cations get bigger so therefore have less of a polarising effect distorting the carbonate ion less. As C-O bond is not weakened as much it harder to break down

Group 1 carbonates do not decompose except for lithium. This is because they don’t have a big enough charge density to polarise the carbonate ion as they only form 1+ ions. However Lithium ion is small enough to have a polarising effect so therefore lithium carbonate can decompose.

Question 24

Explain the reasons for the
trend of thermal stability in
group 1 and 2 nitrates

Answer 24

The ease of thermal decomposition decreases down group 2 and this is because down the group the ions get larger and therefore has less charge density = less polarisation of nitrate anion and less weakening of the N―O bond. Group 1 nitrate do not decompose with the exception of Lithium nitrate. Lithium ion is smaller enough to charge polarisation of the nitrate anion and thus weakening the N-O bond.

Question 25

``` Fill in the flame colours for these group 1 and group 2 elements: Lithium Sodium Potassium Rubidium Caesium Magnesium Calcium Strontium Barium ```

Answer 25

``` Lithium : Scarlet red Sodium : Yellow Potassium : lilac Rubidium : red Caesium: blue Magnesium: no flame colour (the energy emitted is outside visible spectrum) Calcium: brick red Strontium: red Barium: apple green ```

Question 26

How do you carry out a | flame test?

Answer 26

1. Use a nichrome wire 2. Sterilise the wire by dipping in concentrated hydrochloric acid and then heating in Bunsen flame 3. Make sure the sample powdered or grinded 4. Dip wire in solid and put in Bunsen flame and observe flame

Question 27

How are the colours from | the flame test formed?

Answer 27

The heat causes the electron to get excited and thus move to a higher energy level but at this higher level the electron is unstable so then moves back down. As it moves from a higher to lower energy level energy is emitted in the form of visible light energy which is the colour you see.