11 - group 2 Flashcards
alkaline earth metals
elements in group two of the periodic table
Be configuration
1s²
2s²
Mg configuration
1s²
2s² 2p6
3s²
Ca configuration
1s²
2s² 2p6
3s² 3p6
4s²
Sr configuration
1s²
2s² 2p6
3s² 3p6 3d10
4s² 4p6
5s²
Ba configuration
1s²
2s² 2p6
3s² 3p6 3d10
4s² 4p6 4d10
5s² 5p6
6s²
metallic radius of an atom
half the distance between the nuclei in a giant metallic lattice
Be, Mg, Ca, Sr, Ba —–>
. metallic radius increases (each two outer electron occupy a shell further away)
. atomic radius increases
. melting and boiling point decrease
. density increases (Mg lower than Ca)
. decreasing IE (Mg —> Mg2+ + 2e¯)
.reactivity increases (more shielding, more distance between outer electrons and nucleus > nucleus charge)
. solubility decreases
sulfuric acid + Ca/Sr/Ba
. insoluble layer formed on metal surfaces
. reactions stopped
group 2 reactions with oxygen
. burn rapidly
. form white solid oxides
. oxide (eg MgO) is basic in character
. reactivity increases down
. Ba so reactive it is stored under oil
calcium flame test
brick red colour
strontium flame test
scarlet red colour
barium flame test
apple green colour
basic oxide + dilute acid —->
salt + water
which group two oxides are neutralised by dilute HCl
MgO, CaO, SrO, BaO