Question

What is the name of the compound $Ca{{(N{{O}_{3}})}_{2}}$ ?

Answer 1

Naming of compounds is done by the norms and rules set by the international union of pure and applied chemistry (IUPAC). For naming any compound the cations and anions have to be identified, and then the cation is named first followed by anion.

Complete answer:
Any compound containing a metal as one of the formula units attached with more electronegative species, is termed as ionic compounds. Ionic compounds are formed by the transfer of electrons in between the cations and anions of that compound. So, for naming any ionic compound the cation and anion are identified. The cation is the metal that loses electrons which are taken up by the anion.
Here $Ca{{(N{{O}_{3}})}_{2}}$, consist of calcium as the metal ion, $C{{a}^{+}}$cation, and $N{{O}_{3}}^{-}$, which is the nitrate group as the anion. So, the naming will proceed as calcium nitrate. There is a subscript of 2 after the anion, nitrate. This 2 subscript means that 2 electrons have been lost by the metal, which are taken up by the anion, and hence the metal has the valence of 2.
So, according to IUPAC norms, the positive ion, cation is written first, followed by the anion, hence name of $Ca{{(N{{O}_{3}})}_{2}}$ is calcium nitrate.

Note:
The valences of elements are written in case of transition elements, as they have varied valances. For example, copper has +1 and +2 valence, so it is named as copper (II) nitrate in $Cu{{(N{{O}_{3}})}_{2}}$. Also, for a monatomic anion, the name is written with ‘ide’ in the end, for example, for $C{{l}^{-}}$it is named as chloride.