Here's why:

* Ionic bonds occur when one atom (in this case, calcium) loses an electron to another atom (chlorine), resulting in oppositely charged ions that are attracted to each other. Calcium is a metal and tends to lose electrons, while chlorine is a nonmetal and tends to gain electrons.

* Covalent bonds occur when two atoms share electrons. This is common between nonmetals, like hydrogen and nitrogen. Both atoms need electrons to achieve a stable outer shell, and they share electrons to accomplish this.

In summary:

* Calcium chloride (CaCl2) has an ionic bond.

* Hydrogen nitrogen (NH3) has a covalent bond.

They both form compounds, but the types of bonds involved are very different.