A nonpolar covalent bond is a type of chemical bond in which the electrons are shared equally between the atoms. This type of bond is typically found in molecules that are composed of two of the same elements.

MgF2 is an ionic compound, which means that it is composed of positively charged ions (cations) and negatively charged ions (anions). The bond between the magnesium and fluorine atoms in MgF2 is an ionic bond, not a covalent bond.

NaCl is also an ionic compound. The bond between the sodium and chlorine atoms in NaCl is an ionic bond, not a covalent bond.

NH3 is a polar covalent compound. This means that the electrons are not shared equally between the atoms. The nitrogen atom has a slightly negative charge, and the hydrogen atoms have a slightly positive charge.

H2O is also a polar covalent compound. The oxygen atom has a slightly negative charge, and the hydrogen atoms have a slightly positive charge.

N2 is a nonpolar covalent compound. The electrons are shared equally between the two nitrogen atoms.