The oxygen atom found in sodium sulfate, NaSO4, forms bonds with sodium and sulfur. Which bond(s) formed by oxygen would be considered ionic in character? A. Neither the sodium-oxygen bond nor the sulfur-oxygen bond B. The sulfur-oxygen bond, but not the sodium-oxygen bond C. The sodium-oxygen bond, but not the sulfur-oxygen bond D. Both the sodium-oxygen bond and the sulfur-oxygen bond

In sodium sulfate, NaSO₄, oxygen forms different types of bonds with sodium and sulfur.

1. **Sodium-Oxygen Bond**: Sodium (Na) is an alkali metal and tends to lose an electron to form Na⁺. Oxygen (O) is a nonmetal that tends to gain electrons to form O²⁻. The bond between sodium and oxygen involves the transfer of an electron from sodium to oxygen, which characterizes an ionic bond.

2. **Sulfur-Oxygen Bond**: Sulfur (S) is also a nonmetal and can share electrons with oxygen, forming covalent bonds. In sulfate (SO₄²⁻), the sulfur and oxygen atoms share electrons, creating covalent character in the bond.

Based on this understanding, the best choice is:

**C. The sodium-oxygen bond, but not the sulfur-oxygen bond**

The sodium-oxygen bond is considered ionic due to the significant difference in electronegativity and the transfer of an electron, while the sulfur-oxygen bond is primarily covalent.