Write down the formula of potassium dichromate.

Explanation

To write down the formula of potassium dichromate, follow these steps:

### Step 1: Identify the Ions
- Potassium dichromate consists of two types of ions: potassium ions (K⁺) and dichromate ions (Cr₂O₇²⁻).

### Step 2: Write the Symbols and Charges
- The potassium ion has a charge of +1 (K⁺).
- The dichromate ion has a charge of -2 (Cr₂O₇²⁻).
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