An element X has a total of 31 nucleons, out of which 16 are neutrons.
Give the formula of the ion formed by element X.

Explanation

To determine the formula of the ion formed by element X, we can follow these steps:

### Step 1: Determine the number of protons
Given that element X has a total of 31 nucleons (which is the sum of protons and neutrons) and 16 of those are neutrons, we can find the number of protons using the formula:

\[ \text{Number of Protons} = \text{Total Nucleons} - \text{Number of Neutrons} \]

Substituting the values:
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