Group 2/2A: the alkaline earth metals

What is the electron configuration for group 2?

ns^2

What is a common oxidation state for group 2?

2+

They are reactive (strong reducing agents), but less so than Group 1- why?

Because they have two electrons in their final valence electron which would cause them to have 2 electron removed in order to be more stable. Which is significantly more energy required to remove these electrons

Why is the period 2 element in group 2 different yet again?

It has a high charge density which give it more covalent character than the other larger, more ionic G2 metals.

What does High charge density mean?

A large amount of electric charge is concentrated in a small volume. It causes greater polarization which causes it to be shared with other elements.

Is BeO basic or acidic? and whats the general trend for other G2 metal oxides?

BeO is amphoteric, all other metal oxides are only basic!

Group 2 reacts with O2 to make metal oxides

Ex: 2Mg (s) + O2 (g) -> 2MgO (s)

Ba will also make a peroxide

Ex: Ba (s) + O2 (g) -> 2BaO2 (s)

Larger group 2 metals (Ca, Sr, Ba) are strong enough reducing agents to reduce H2O to make/displace H2 gas in exothermic reactions

Ex: Ca(s) +2H2O(l) -> Cs(OH)2(aq) + H2(g)

Group 2 react with N2 to make metal nitrides (Mg at all T, other metals only at high T)

Ex: 3Sr(s) +N2 (g) -> Sr3N2 (s) at HIGH T

Group 2 oxides + CO2 = carbonates

Ex: SrO(s) +CO2 (g) ->SrCO3 (s)

All Group 2 Carbonates decompose with heat

limestone to lime Ex: CaCO3 (s) -> CaO (s) + CO2 (g)

Diagonal relationship

Similarities in properties between a period (row) 2 element and period 3 element, one group to the right. Ex: Li+, Mg2+ or Be, Al

G1/2 oxides are BASIC!

exception: BeO is also amphoteric!

Slacked lime?

Ca(OH)2

Limestone?

CaCO3

Normal lime?

CaCO