Which two elements are in same period as well as same group of modern periodic table ?

Options

A. Z = 23, Z = 31
B. Z = 65, Z = 66
C. Z = 52, Z = 87
D. Z = 58, Z = 46

Answer

To determine which two elements are in the same period as well as the same group in the modern periodic table, we can follow these steps:

### Step 1: Understand the Structure of the Periodic Table
The periodic table is organized into periods (horizontal rows) and groups (vertical columns). Elements in the same group have similar chemical properties, and elements in the same period have the same number of electron shells.

### Step 2: Identify the Relevant Periods and Groups
In the context of the question, we need to focus on the lanthanoids and actinoids, which are located in periods 6 and 7, respectively.

- **Lanthanoids**: These elements range from atomic number 57 (Lanthanum) to 71 (Lutetium).
- **Actinoids**: These elements range from atomic number 89 (Actinium) to 103 (Lawrencium).

### Step 3: Look for Elements in the Same Period and Group
We need to find elements that are both in the same period and the same group.

- For lanthanoids, they all belong to the f-block and are in period 6.
- For actinoids, they also belong to the f-block and are in period 7.

### Step 4: Analyze the Given Options
We need to check the options provided to see which pairs of elements fall within the ranges of the lanthanoids and actinoids.

1. **Option 1: 23 and 31** - These elements are not in the lanthanoid or actinoid series.
2. **Option 2: 65 and 66** - Both elements fall within the range of lanthanoids (57 to 71).
3. **Option 3: 52 and 87** - Both elements are outside the range of lanthanoids and actinoids.
4. **Option 4: 58 and 46** - 58 is in the range of lanthanoids, but 46 is not.

### Step 5: Conclusion
From the analysis, the only pair of elements that are in the same period and same group is **65 (Terbium) and 66 (Dysprosium)**, both of which are lanthanoids.

### Final Answer
The two elements that are in the same period as well as the same group are **Terbium (Tb, atomic number 65) and Dysprosium (Dy, atomic number 66)**.

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