Group 2 Metals Flashcards
What is the trend in melting points as you go down group 2?
Melting points decrease
- this is due to the larger radii as you go down the group
- this leads to the free electrons having less attraction to the nucleus
What is the trend in ionisation energy down group 2
It decreases as you go down the group, this is due to the atomic radii increasing.
What do group 2 metals react with water to form?
What happens to the reactivity as you go down group 2?
Metal hydroxide salt M(OH)2 + hydrogen gas H2 ;except beryllium
-The salt dissociates into metal ions and hydroxide ions giving an alkaline pH
Reactivity increases, this is because ionisation energy decreases
What does the first ionisation look like?
M -> M+ + e-
What type of reaction occurs between group 2 elements and oxygen?
This is a vigorous redox reaction which produces a metal oxide: MO
What is the trend in the solubility of the group 2 metal hydroxides?
Solubility increases
What is the trend in the solubility of the group 2 metal sulfates?
The solubility decreases down the group
What do group 2 metals react with dilute acids to produce?
Dilute acids to produce a salt and hydrogen
Eg Ca + H2SO4 -> CaSO4 + H2
Reactivity increases down the group due to the decrease in ionisation energies
Salts produced become less soluble
What do MO and H2O react to form?
M(OH) which when dissolved dissociates into M+ and OH- ions giving a basic solution
The more solubility the more basic the solution
Solubility increases down the group
What is milk of magnesia?
A treatment used for indigestion known to neutralise stomach acid (an antacid)
-magnesium hydroxide :
Mg(OH)2 + 2HCl -> MgCl2 + 2H2O
What is calcium carbonate used in? (CaCO3)
Building material such as marble and limestone
Unfortunately reacts readily with acids(rainwater has an acidic pH) leading to gradual erosion
CaCO3 + 2HCl -> CaCl2 + H2O + CO2
