Statement I: In writing the electronic configuration of an atom, the 5s orbital will be filled before 4p orbital.
Statement II: The (n + l) values for 5s orbital and 4p orbital are identical.

Options

A. If both Statement I and Statement II are true and Statement II is the correct explanation of Statement I.
B. If both Statement I and Statement II are true but Statement II is not the correct explanation for Statement I.
C. If Statement I is true but Statement II is false.
D. If Statement I is false but Statement II is true.

Answer

To solve the problem, we need to analyze both statements given in the question.

### Step 1: Analyze Statement I
Statement I claims that the 5s orbital will be filled before the 4p orbital.

- According to the Aufbau principle, electrons fill orbitals starting from the lowest energy level to the highest.
- The order of filling is determined by the (n + l) rule, where 'n' is the principal quantum number and 'l' is the azimuthal quantum number.
- For the 5s orbital, n = 5 and l = 0, so (n + l) = 5 + 0 = 5.
- For the 4p orbital, n = 4 and l = 1, so (n + l) = 4 + 1 = 5.

Since both orbitals have the same (n + l) value, we need to consider the principal quantum number 'n' to determine which orbital has lower energy. The 5s orbital has a higher principal quantum number (n = 5) compared to the 4p orbital (n = 4), which means the 5s orbital is at a higher energy level than the 4p orbital.

Thus, the 4p orbital will be filled before the 5s orbital.

### Conclusion for Statement I:
Statement I is **false**.

### Step 2: Analyze Statement II
Statement II states that the (n + l) values for the 5s orbital and the 4p orbital are identical.

- As calculated above, the (n + l) value for the 5s orbital is 5, and for the 4p orbital, it is also 5.
- Therefore, the (n + l) values for both orbitals are indeed identical.

### Conclusion for Statement II:
Statement II is **true**.

### Final Conclusion:
- Statement I is false, and Statement II is true. Therefore, the correct answer is that Statement I is false, and Statement II is true.