It each orbital can hold a maximum of three electrons, the number of elements in 9th period of periodic table (long form) are:

Options

A. 48
B. 162
C. 50
D. 75

Answer

To determine the number of elements in the 9th period of the periodic table, given that each orbital can hold a maximum of three electrons, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Types of Orbitals**:
The types of orbitals in a period are s, p, d, and f. Each type has a specific number of orbitals:
- s orbital: 1 orbital
- p orbital: 3 orbitals
- d orbital: 5 orbitals
- f orbital: 7 orbitals

2. **Calculate the Total Number of Orbitals**:
For the 9th period, we need to sum the number of orbitals:
\[ \text{Total orbitals} = 1 \, (\text{s}) + 3 \, (\text{p}) + 5 \, (\text{d}) + 7 \, (\text{f}) = 16 \text{ orbitals} \]

3. **Determine the Maximum Number of Electrons**:
Since each orbital can hold a maximum of 3 electrons, we multiply the total number of orbitals by 3:
\[ \text{Total electrons} = \text{Total orbitals} \times 3 = 16 \times 3 = 48 \]

4. **Conclusion**:
Therefore, the number of elements in the 9th period of the periodic table is 48.

### Final Answer:
The number of elements in the 9th period of the periodic table is **48**.

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