Assign the position of the element having outer electronic configuration,
(A) `ns^(2)np^(2)` (n=6)
(B) `(n-1)d^(2)ns^(2)" "(n=4)`
(C) `(n-2)f^(7)(n-1)d^(-1)ns^(2)` (n=6)
Which of the following statement(s) is/are correct?

Options

A. The element 'A' belong to 3rd period and 16th group.
B. The element 'B' belong to 4th period and 4th group
C. The element 'C' belong to 6th period and 3rd group and is lanthanide element.
D. All A, B , C elements are metals

Answer

To solve the question, we need to assign the position of the elements based on their outer electronic configurations. Let's break it down step by step.

### Step 1: Analyze the given outer electronic configurations

**(A) `ns^(2)np^(2}` (n=6)**
This means the outer configuration is `6s^2 6p^2`.
- Since n=6, the element is in the 6th period.
- The outermost electrons are in the s and p orbitals, indicating it is a p-block element.
- The group can be determined as follows: `ns^2` contributes to group 2 and `np^2` contributes to group 14. Thus, the element belongs to group 14.
- The element with this configuration is Lead (Pb), which has an atomic number of 82.

**Position:** 6th period, Group 14.

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**(B) `(n-1)d^(2)ns^(2)` (n=4)**
This means the outer configuration is `3d^2 4s^2`.
- Here, n=4 indicates that the element is in the 4th period.
- The presence of `d` electrons indicates that it is a transition metal.
- The element with this configuration is Titanium (Ti), which has an atomic number of 22.

**Position:** 4th period, Group 4.

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**(C) `(n-2)f^(7)(n-1)d^(-1)ns^(2)` (n=6)**
This means the outer configuration is `4f^7 5d^1 6s^2`.
- Here, n=6 indicates that the element is in the 6th period.
- The presence of `f` electrons indicates that it is an inner transition metal (Lanthanide series).
- The element with this configuration is Gadolinium (Gd), which has an atomic number of 64.

**Position:** 6th period, Group 3.

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### Step 2: Summarize the positions of the elements

- **Element A (Lead):** 6th period, Group 14.
- **Element B (Titanium):** 4th period, Group 4.
- **Element C (Gadolinium):** 6th period, Group 3.

### Step 3: Evaluate the statements

1. **Statement A:** "Element A belongs to 3rd period."
- **Evaluation:** Incorrect, as it belongs to the 6th period.

2. **Statement B:** "Element B belongs to 4th period and 4th group."
- **Evaluation:** Correct, as it belongs to the 4th period and Group 4.

3. **Statement C:** "Element C belongs to 6th period and 3rd group."
- **Evaluation:** Correct, as it belongs to the 6th period and Group 3.

4. **Statement D:** "All elements A, B, C are metals."
- **Evaluation:** Incorrect, as Lead (A) is a metal, Titanium (B) is a metal, but Gadolinium (C) is a metal, but the statement is misleading as it does not specify that A is a metal.

### Final Conclusion

The correct statements are B and C.

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