Answer:
The answer is: the number of unpaired valence electrons
Explanation:
The valence electrons are the number of electrons present in outer shell of an atom that participate in chemical bond formation, if the outer shell is not completely filled.
Covalent bond formation occurs when two atoms contribute one valence electron each to form a bond. Thus the number of covalent bonds that an element can form, can be determined by the number of unpaired valence electrons.
Therefore, the nature and the number of bonds formed by the element and the chemical properties of the element can be determined by the number of valence electrons present in the outer shell of the element.
