Nitric acid four-covalent

Moving now to nitrogen we see that it has four covalent bonds (two single bonds + one double bond) and so its electron count is 5(8) = 4 A neutral nitrogen has five electrons m its valence shell The electron count for nitrogen m nitric acid is one less than that of a neutral nitrogen atom so its formal charge is +1... 

The N atom in nitric acid has four covalent bonds, thereby exceeding its normal covalency of three. The N atom also bears a formal charge. These circumstances are related. Invariably, an atom with an octet of electrons will have a formal charge when not exhibiting its normal covalency. (See Problem 8, page 143.)... 

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