Periodicity: Group 2, Alkaline Earth Metals - Trends

Question 1

Describe the trend in atomic radius as you descend group 2

Answer 1

• Atomic radius increases

- Number of electron shells increase as you descend group

Question 2

Describe the trend in first ionisation energy as you descend group 2

Answer 2

• First ionisation energy decreases
• More electron shells, means outer electrons are further away from nucleus
• Increased shielding
• Weaker attraction of ion to lost electrons

Question 3

Describe the trend in reactivity as you descend group 2

Answer 3

• When group 2 elements react, they lose electrons, forming positive ions
• The easier it is to remove electrons (the lower the first ionisation energy), the more reactive the element
• Reactivity increases down the group

Question 4

Describe the trend in melting point from Mg-Ba

Answer 4

• Melting points generally decrease (Mg decreases by a significant amount)
• Metallic bonds are weaker
• Size of the metal ion increases, resulting in less attraction between the nucleus of the positive ions and the delocalised electrons

Question 5

Describe the trend in reactivity with water as you descend group 2

Answer 5

• Reactivity with water increases