2.2.1 Trends in Group 2 : Alkaline earth metals

Question 1

Noteson Alkaline metals

Answer 1

• 2+ charge
• Ionic compounds
• Reducing agents
• Down group more reactive

Question 2

Why do group 2 elements become more reactive going down the group?

Answer 2

• Ionisation energy decreases down group
• Nuclear charge increases
• But shielding increases
• Atomic radius increases (greater distance from protons in nucleus to outer electrons)
• So these 2 outweigh the increasing nuclear charge
• Less energy required to lose electrons, so more reactive going down group

Question 3

Examples of how reactivity increases going down group 2?

Answer 3

With dilute HCL, bubbles of H2 gas are given off more vigorously.

With oxygen, barium needs to be stored in oil to prevent reacting with O2 in air

Question 4

What are the physical trends going down group 2?

Answer 4

• Melting point decreases
• Atomic radius increases
• So attraction between nucleus and bonding electrons decreases
• Causing decrease in melting point