Group 2 Flashcards
Trend in atomic radius
Increases down group- electrons in shells further from the nucleus
Trend in ionic size
Increases down the group because the nuclear charge is greater than the electronic charge
Trend in melting points
Decreases down the group because the bonds get weaker due to increased size and lower charge density
Trend in reactivity
Increases down the group as cation formation becomes easier
Trend in ionisation
Decreases down the group as atomic size increases due to increased shielding from the inner shells, meaning there is more repulsion of the outer electrons
Why are group 2 IE values higher than their group 1 equivalents?
Increased nuclear charge in group 2 so higher attraction from the nucleus
Why is there a large increase for 3rd IE’s?
Electrons are being removed from a shell nearer the nucleus, so there is less shielding so more energy is required to overcome the attraction between the nucleus and the 3rd electron
Trend in reactions with oxygen (O2)
Increasing vigour down the group:
- Mg burns readily with a bright white flame
- Ba burns readily with an apple-green flame
Trends in reactions with water (H2O)
Reacts with increasing vigour down the group:
- Mg reacts very slowly with cold water but quickly with steam
- Ba reacts vigorously with cold water
Trend in reactions with dilute acid (H+)
React with increasing vigour down the group to produce a salt and hydrogen
Properties of group 2 oxides
Ionic solids except from beryllium oxide which has covalent character
Reactions of group 2 oxides with water
Produce hydroxides except from BeO which doesn’t react
Trend in basic strength of GRP2 hydroxides
Increases down the group as solubility increases:
- metal ion gets larger so charge density decreases
- lower attraction between OH- ions and larger dispositive ions
-ions will split away from each other more easily
- greater concentration of OH- ions in the water
Uses of GRP2 hydroxides
Ca(OH)2 is used in agriculture to neutralise acidic soil
Mg(OH)2 is used in toothpaste and indigestion tablets as an antacid
Properties of GRP2 Carbonates
- Insoluble in water
- Undergo thermal decomposition to become white oxides and CO2
