Chromite ore has the formula `"…...................."`.

Answer

To determine the formula of chromite ore, we can follow these steps:

### Step 1: Identify the components of chromite ore
Chromite ore is primarily composed of iron (Fe), chromium (Cr), and oxygen (O).

### Step 2: Determine the oxidation states of the elements
- Iron (Fe) can have multiple oxidation states, but in chromite, it is typically in the +2 oxidation state.
- Chromium (Cr) is commonly found in the +3 oxidation state in chromite.
- Oxygen (O) generally has a -2 oxidation state.

### Step 3: Write the formula based on the components and their oxidation states
To balance the charges, we need to consider the number of each atom:
- For every 2 chromium ions (each with a +3 charge), the total positive charge is +6.
- To balance this, we need 3 oxide ions (each with a -2 charge), which gives a total negative charge of -6.

### Step 4: Combine the elements to form the formula
The formula for chromite ore can be constructed as follows:
- 1 Fe ion contributes +2 charge.
- 2 Cr ions contribute +6 charge.
- 4 O ions contribute -8 charge.

Thus, the overall formula is:
\[ \text{Fe}^{2+} + 2 \text{Cr}^{3+} + 4 \text{O}^{2-} \]
This simplifies to:
\[ \text{FeCr}_2\text{O}_4 \]

### Final Answer
The formula of chromite ore is **FeCr₂O₄**.

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