Group 2
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What happens to the atomic radius down group 2?
Atomic radius gets bigger down the group More shells of electrons.
What happens to the ionisation energy down group 2?
Decreases Atomic radius gets bigger More shielding Attraction between nucleus and outer shell electron decreases.
What happens to the melting points down the group?
Decreases Weaker metallic bonding as atoms bigger Change in trend after Mg due to change in way atoms pack together.
Give the observation made when Mg reacts with water
No reaction (well, very slow) with cold water. Burns with white flame to form white powder with steam.
What is the equation when Mg reacts with water?
Mg + H2O –> MgO+ H2
Give the observation made when Ca reacts with water.
Fizzes in water and after a time, white solid forms The solid is Ca(OH)2 which is slightly soluble in water.
What is the equation when Ca reacts with water?
Ca + 2 H2O –> Ca(OH)2 + H2
Give the observation made when Sr reacts with water.
Fizzes in water and forms a colourless solution.
What is the equation when Sr reacts with water?
Sr + 2 H2O –> Sr(OH)2 + H
Give the observation made when Ba reacts with water.
Fizzes in water and forms a colourless solution.
What is the equation when Ba reacts with water?
Ba + 2 H2O –> Ba(OH)2 + H2
What is the trend in reactivity?
Becomes more reactive down the group.
Explain the trend down the group.
When the metals react they lose their two outer shell electrons. Down the group, atoms become bigger and there is more shielding. Therefore there is a weaker attraction between the nucleus and the outer shell electrons and so the outer shell electrons are more easily lost.