Heated, it shrinks when cooled
well you can't walk through the air but you can't walk through a concrete wall because all of the solid atoms holding it together
Valency is the number of electrons lost or gained by an atom to attain an stable configuration. Valency is important when writing the formula of chemical compounds in chemistry. Strontium has a valency of 2 while sulfite ion (radicle) has a valency of 2. Therefore, the chemical formula of strontium sulfite is written as SrSO3.