Group 2 Flashcards
Group 2 electrons all have
2 outer electrons in their outer shell S^2
oxidation state of group 2 when they react
0 –> +2
Loss of electrons when group 2 metals react
M—> M^2+ + 2e^-
When group 2 elements react with water
Metal hydroxide and hydrogen
Ca + H2O —–>
Ca(OH)2 + H2
Why do the ionisation energies decrease down the group?
Increasing atomic radii. And increasing shielding effect.
When group 2 metals react with oxygen
You get solid white oxides (solid)
Oxides of group 2 metals react with water to form
Metal hydroxides, which dissolve. Depending on the solubility of the ion, the more alkaline it is.
More soluble = more alkaline (down group)
Why is magnesium oxide an exception to making hydroxide alkaline solutions
It reacts slowly and the hydroxide isn’t very soluble
Group 2 with dilute acids
M(s) + 2HCL –> MCL(2) + H2
Use of calcium hydroxide (slaked lime)
Agriculture- neutralises acidic soils (moderation)
Magnesium hydroxide and calcium carbonate
Indigestion tablets to neutralise stomach acid.
Trend in reactivity down group 2
When group 2 elements react they lose electrons, forming positive cations. It’s easier to lose more electrons when there is a lower first and second ionisation energy.
Ionisation energy decreases down the group- reactivity increases down the group
