Which is more covalent $\mathrm{NaCl}\mathrm{or}\mathrm{CuCl}$?

1. Sodium is a chemical element with an atomic number$11.$
2. Copper is also a chemical element with an atomic number $29.$
3. The electronic configuration of Sodium is $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^1$.
4. Copper is an exception, to attain stability it changes the electronic configuration in its ground state.
5. The electronic configuration of Copper is $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{1}3{\mathrm{d}}^{10}$
6. Sodium loses its one electron to form cation whereas Chlorine attains one electron and becomes an anion.
7. Thus, they form ionic or electrovalent compounds.
8. Copper mutually shares the electron with the Chlorine atom to form Copper chloride.
9. In this way Copper chloride forms the covalent bond.
10. Hence we concluded that Copper chloride ($\mathrm{CuCl}$) is more covalent in nature compared with Sodium Chloride ($\mathrm{NaCl}$).