Question

which is an example of a monatomic ion?
na+
nh4+
co32-
no3-
so42-
a polyatomic ion is best described as
a single atom with no charge
a group of covalently bonded atoms that together carry a net charge
a single metal atom that lost electrons
any pair of atoms with a covalent bond
a neutral atom with extra neutrons

Explanation:

First Question: Which is an example of a monatomic ion?

A monatomic ion is an ion consisting of a single atom. Let's analyze each option:

• \( \text{Na}^+ \): This is a sodium ion, formed from a single sodium atom (lost one electron), so it's monatomic.
• \( \text{NH}_4^+ \): This is the ammonium ion, consisting of one nitrogen and four hydrogen atoms (a group of atoms), so it's polyatomic.
• \( \text{CO}_3^{2-} \): Carbonate ion, with one carbon and three oxygen atoms, polyatomic.
• \( \text{NO}_3^- \): Nitrate ion, with one nitrogen and three oxygen atoms, polyatomic.
• \( \text{SO}_4^{2-} \): Sulfate ion, with one sulfur and four oxygen atoms, polyatomic.

Let's analyze each option:

• "a single atom with no charge": This describes a neutral atom, not an ion (let alone polyatomic). Eliminate.
• "a group of covalently bonded atoms that together carry a net charge": Polyatomic ions are groups of atoms (covalently bonded within the group) with a net positive or negative charge. This matches.
• "a single metal atom that lost electrons": This is a monatomic cation, not polyatomic. Eliminate.
• "any pair of atoms with a covalent bond": This is a covalent molecule or part of a molecule, not necessarily an ion (and polyatomic ions can have more than two atoms). Eliminate.
• "a neutral atom with extra neutrons": This describes an isotope, not an ion. Eliminate.

Answer:

\( \text{Na}^+ \) (the first option: \( \text{Na}^+ \))

Second Question: A polyatomic ion is best described as