Give reasons
has valency
Magnesium
two
a

Magnesium has valency equal to 2 +

Explanation:

because the electronic configuration of Mg is [2,8,2]. The nearest noble gas to magnesium is neon with electronic configuration of [2,8], to achieve this stable electronic configuration Mg can lose 2 valence electrons, hence its valency is 2 + .

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).