3.2.2 Group 2, the alkaline earth metals

Question 1

What happens to the atomic radius of group 2 metals as we go down the group and why?

Answer 1

Atomic Radius increases

Question 2

Definition of first ionisation energy

Answer 2

Energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous 1+ ions.

Question 3

What happens to first ionisation energy as we move down group 2?

Answer 3

Increases, extra shells added, more shielding and weaker attraction between the nucleus and outermost electron. Proton number also increases but shielding overrides this. Therefore, less energy is required to remove those outermost electrons.

Question 4

What is the general trend in melting points down group 2?

Answer 4

Decreases, down the group size of metal ion increases but the number of delocalised electrons remains the same. Distance between positive nuclei and delocalised electrons increases, attractive forces weaken making it easier to loosen metallic bonds.

Question 5

Group 2 metals burn in oxygen, what observation can be made with this reaction : 2Mg + O2 = 2MgO

Answer 5

Mg burns with a brigh white flame.

Question 6

What happens to reactivity down group 2

Answer 6

Increases

Question 7

Mg reacts with steam to produce…

Answer 7

Magnesium oxide and hydrogen

Question 8

Observations of Mg reacting with steam

Answer 8

Bright white flame/light

Question 9

Mg reacts with warm water to produce…

Answer 9

Magnesium hydroxide and hydrogen

Question 10

Observation when Mg reacts with warm water