Suppose an orbital may accomodate 3 electrons then the number of elements in IV period.

Options

A. 18
B. 27
C. 12
D. 45

Explanation

To solve the question about how many elements can be accommodated in the fourth period if each orbital can hold three electrons, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Orbitals in the Fourth Period:**
The fourth period of the periodic table includes the following orbitals:
- 4s
- 3d
- 4p

2. **Count the Number of Orbitals:**
- The 4s orbital has **1 orbital**.
- The 3d subshell has **5 orbitals**.
- The 4p subshell has **3 orbitals**.

Therefore, the total number of orbitals in the fourth period is:
\[ 1 \, (4s) + 5 \, (3d) + 3 \, (4p) = 9 \, \text{orbitals} \]

3. **Determine the Electron Capacity:**
According to the question, each orbital can accommodate **3 electrons**.

4. **Calculate the Total Number of Electrons:**
To find the total number of electrons that can be accommodated in the fourth period, we multiply the number of orbitals by the number of electrons each can hold:
\[ 9 \, \text{orbitals} \times 3 \, \text{electrons/orbital} = 27 \, \text{electrons} \]

5. **Conclusion:**
Therefore, if each orbital can accommodate three electrons, the total number of elements in the fourth period is **27**.

### Final Answer:
The number of elements in the fourth period, given that each orbital can accommodate three electrons, is **27**.

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