Summarise the rules for writing of distribution of electrons in various shells for the first eighteen elements.

Explanation

To summarize the rules for writing the distribution of electrons in various shells for the first eighteen elements, we can follow these steps:

### Step 1: Understand the Formula for Maximum Electrons in a Shell
The maximum number of electrons that can be accommodated in a shell is given by the formula:
\[ \text{Maximum electrons} = 2n^2 \]
where \( n \) is the principal quantum number (or shell number).

### Step 2: Calculate Maximum Electrons for Each Shell
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