Number of oxygen atoms in molybdate ion is

Answer

To determine the number of oxygen atoms in the molybdate ion, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Molybdate Ion**: The molybdate ion is represented as \( \text{MoO}_4^{2-} \). This indicates that it contains molybdenum (Mo) and oxygen (O) atoms.

2. **Determine the Composition of the Ion**: The formula \( \text{MoO}_4^{2-} \) tells us that there are four oxygen atoms (O) associated with one molybdenum atom (Mo).

3. **Count the Oxygen Atoms**: From the formula \( \text{MoO}_4^{2-} \), we can see that there are 4 oxygen atoms in total.

4. **Conclusion**: Therefore, the number of oxygen atoms in the molybdate ion is 4.

### Final Answer:
The number of oxygen atoms in the molybdate ion is **4**.