Module 2: Group 2 elements Flashcards
Whats the electron configuration of group elements?
[NG] s2
What is the group 2 trend in reactivity?
- Rate of Reactivity increases:
- Shielding increases
- Nuclear attraction on outer electron decreases
- Atomic radius increases
- Ionisation energies decrease
Whats the observation for the reaction of group 2 elements with oxygen?
Observations: - Bright white light
- Solid formed
Write an equation for the reaction of magnesium with oxygen.
Mg(s) + 1/2 O2 (g) ——-> MgO (s)
What’s the equation for a reaction of a group 2 element with water?
M(s) + 2H2O(l) ———> M(OH)2 (aq) + H2 (g)
What are observations for the reaction of these elements with water?
- Dissolving metal
- Fizzing
Whats the solubility of metal oxides?
Solubility gets higher going down the group - PH also increases as the metal dissolves faster in water to release OH- ions (alkaline ion)
What is the equation for the reaction of group 2 elements with dilute acids?
M(s) + 2HCl ——-> MCL2 (aq) + H2 (aq)
** Note - these can’t be neutralisation reactions as they are redox
What is the reaction of group 2 compounds with acids?
Neutralisation reaction
What are MO and M(OH)2?
These are bases as they are soluble so form alkaline ions (OH-)
What is an acid?
A proton (H+) donor
What’s methanoic acid?
CH3COOH
What’s the use for Mg(OH)2?
Medicine, antacids - neutralises stomach acids
Mg(OH)2 + 2HCl ——> MgCl2 + 2H2)
What’s the name of the reaction that takes place between a base and an acid?
Nuetralisation reaction
What’s the use for Ca(OH)2?
It neutralises soils (H2SO4).
Ca(OH)2 + H2SO4 ——–> CaSO4 + H2O
What’s the use for CaCO3?
Thermal decomposition gives CaO which can be used in cement.
CaCO3 + heat ——–> CaO + CO2
