In a polyatomic ion such as the ammonium ion, `NH_4^(+)`, the atoms are held together by

Options

A. ionic bonds
B. covalent bonds
C. both ionic and covalent bonds
D. nondirectional bonds

Answer

B

Explanation

A polyatomic ion is an ion that contains more than one atom. These atoms are held together by covalent bonds which can be represented by the Lewis formula.
`[H:overset(H)overset(ddot)underset(H)underset(ddot)(N):]^(+)` or `[H-overset(H)overset(|)underset(H)underset(|)(N)-H]`
Note that the Lewis formula for the ammonium ion, `NH_4^(+)`, shows only 8 electrons, even though the N atom has 5 electrons in its valence shell and each H atom has one giving a total of `[5+4(1)=]9` electrons. A deficiency of one electron relative to the neutral atoms is due to the `1+` ionic charge carried by the ammonium ion.