3.2.2 - group 2

why does atomic radius increase down the group

atoms have more shells of electrons

trend of melting points down the group and why

• decreases

• as atomic size increases, metallic bonding weakens

• because distance btw positive ions and delocalized e-s increases

• so force of attraction btw them weakens

trend in 1st ionization energy down the group and why

• Decreases down the group

• Bc distance between nucleus and outer electrons successively increases

• Also increased shielding of nucelus by inner shells of e-s

• So there is a weaker force of attraction between the nucleus and outer e-

• So outermost e- = requires less energy to remove

Trend of reactivity down group 2

Increases

REACTIONS OF GROUP 2 METALS WITH OXYGEN - what do they all do in the presence of oxygen

Burn in it

What does Mg burn with

Give an equation for this

What is the product of this rxn (colour and state)

A bright white flame

2Mg + O2 —→2MgO

White solid, has a high m.p.

IDK IF YOU NEED THIS BUT

Can Mg react slowly with oxygen without a flame

Equation for this

What will the Mg ribbon have a thin layer of on it (will need to be cleaned off before doing rxns with the ribbon)

What would happen if you didn't clean it off

Yes

2Mg + O2 —→2MgO (same as before)

MgO

would give a false result because both the Mg and MgO would react but at different rates.

Mg + 2HCl  MgCl2 + H2

MgO + 2HCl  MgCl2 + H2O