Explanation:
Valence electrons are defined as the electrons present in the outermost shell of an atom.
(a) As, atomic number of fluorine is 9 and its electronic distribution is 2, 7. Hence, there are 7 valence electrons present in a fluorine atom. And, to attain stability it will readily gain one electron from a donor atom. Hence, it will make a single bond.
Therefore, fluorine has 7 valence electrons and makes 1 bond in neutral compounds.
(b) As, atomic number of nitrogen is 7 and its electronic distribution is 2, 5. Hence, there are 5 valence electrons present in a nitrogen atom. And, to attain stability it will gain three electrons from a donor atom. Hence, it will make a triple bond.
Therefore, nitrogen has 5 valence electrons and makes 3 bonds in neutral compounds.
(c) As, atomic number of carbon is 6 and its electronic distribution is 2, 4. Hence, there are 4 valence electrons present in a carbon atom. And, to attain stability it will readily share its valence electrons with another atom. Hence, it will make four bonds.
Therefore, carbon has 4 valence electrons and makes 4 bonds in neutral compounds.
(d) As, atomic number of oxygen is 8 and its electronic distribution is 2, 6. Hence, there are 6 valence electrons present in an oxygen atom. And, to attain stability it needs 2 electrons from another atom. Hence, it will make double bond.
Therefore, oxygen has 6 valence electrons and makes 2 bonds in neutral compounds.
