If P.T would have contained 10 periods, maximum elements in that P.T. would be :-

Options

A. 72
B. 190
C. 144
D. 290

Explanation

To solve the question regarding the maximum number of elements in a periodic table with 10 periods, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of the Periodic Table**:
The periodic table is organized into periods (horizontal rows) and groups (vertical columns). Each period corresponds to the principal quantum number (n) of the elements.

2. **Identify the Formula for Maximum Elements**:
For an even number of periods (n), the maximum number of elements can be calculated using the formula:
\[ \text{Maximum Elements} = \frac{(n + 2)^2}{2} \]

3. **Substitute the Number of Periods**:
In this case, we have 10 periods (n = 10). We will substitute this value into the formula:
\[ \text{Maximum Elements} = \frac{(10 + 2)^2}{2} \]

4. **Calculate the Expression**:
First, calculate \(10 + 2\):
\[ 10 + 2 = 12 \]
Now, square this result:
\[ 12^2 = 144 \]
Finally, divide by 2:
\[ \frac{144}{2} = 72 \]

5. **Conclusion**:
Therefore, the maximum number of elements in a periodic table with 10 periods is 72.

### Final Answer:
The maximum number of elements in a periodic table with 10 periods is **72**.

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