N forms 3 covalent bonds, H forms 1 covalent bond, and O forms 2 covalent bonds.
The number of covalent bonds that an atom typically forms is determined by its valence electrons, which are the outermost electrons involved in bonding. In covalent bonding, atoms share electrons to achieve a more stable electron configuration.
Nitrogen (N) has five valence electrons, and it forms three covalent bonds. This is because nitrogen needs three more electrons to achieve a stable octet, and by sharing electrons with three other atoms, it can complete its outer shell.
Hydrogen (H) has one valence electron and tends to form a single covalent bond. Since hydrogen only needs one more electron to achieve a stable configuration resembling helium, it shares its electron with another atom to form a bond.
Oxygen (O) has six valence electrons and typically forms two covalent bonds. Oxygen needs two additional electrons to complete its outer shell, and by sharing electrons with two other atoms, it achieves a stable electron configuration.
These trends in covalent bonding are based on the octet rule, which states that atoms tend to gain, lose, or share electrons to achieve a stable configuration with eight electrons in their outer shell. The specific number of bonds formed by an atom is influenced by its electron configuration and the number of electrons needed to reach a stable state.