To determine the number of oxygen atoms in one formula unit of sodium chromate, represented by the chemical formula [tex]\( \text{Na}_2\text{CrO}_4 \)[/tex], follow these steps:
1. Break down the chemical formula [tex]\( \text{Na}_2\text{CrO}_4 \)[/tex] into its constituent elements: sodium (Na), chromium (Cr), and oxygen (O).
2. Identify the subscript next to each element in the formula:
- Sodium (Na) has a subscript of 2.
- Chromium (Cr) has no subscript, which means it is understood to be 1.
- Oxygen (O) has a subscript of 4.
3. The subscript next to oxygen (O) indicates the number of oxygen atoms present in one formula unit of sodium chromate. Here, the subscript is 4, which means there are 4 oxygen atoms.
Therefore, the number of oxygen atoms in one formula unit of sodium chromate ([tex]\( \text{Na}_2\text{CrO}_4 \)[/tex]) is [tex]\( \boxed{4} \)[/tex].
