The number of elements in each of the long periods in the periodic table is

Options

A. 2
B. 8
C. 18
D. 32

Answer

To determine the number of elements in each of the long periods in the periodic table, we need to analyze the structure of the periodic table, particularly focusing on the long periods.

### Step-by-Step Solution:

1. **Identify the Long Periods**:
The long periods in the periodic table are Periods 6 and 7. These periods contain the transition metals and the inner transition metals (lanthanides and actinides).

2. **Count the Elements in Period 6**:
- Period 6 starts with cesium (Cs) and ends with radon (Rn).
- This period includes the following blocks:
- s-block: 2 elements (Cs, Ba)
- d-block: 10 elements (from La to Hg)
- p-block: 6 elements (from Tl to Rn)
- Total for Period 6 = 2 (s-block) + 10 (d-block) + 6 (p-block) = 18 elements.

3. **Count the Elements in Period 7**:
- Period 7 starts with francium (Fr) and ends with oganesson (Og).
- This period also includes:
- s-block: 2 elements (Fr, Ra)
- d-block: 10 elements (from Rf to Cn)
- f-block: 14 elements (lanthanides from La to Lu, and actinides from Ac to Lr)
- p-block: 6 elements (from Nh to Og)
- Total for Period 7 = 2 (s-block) + 10 (d-block) + 14 (f-block) + 6 (p-block) = 32 elements.

4. **Summarize the Total Elements in Long Periods**:
- Period 6 has 18 elements.
- Period 7 has 32 elements.
- Therefore, the total number of elements in both long periods = 18 + 32 = 50 elements.

### Final Answer:
The number of elements in each of the long periods in the periodic table is:
- Period 6: 18 elements
- Period 7: 32 elements