Which one of the following statements concerning the electrons specified by the notation `3p^(4)` is true?

Options

A. The electrons are in the M shell
B. The electrons are in the `l=2` subshell
C. The electrons are necessarily in an excited state
D. They have principal quantum number 4

Answer

To solve the question regarding the electrons specified by the notation `3p^(4)`, we will analyze the notation step by step.

### Step-by-Step Solution:

1. **Understanding the Notation**:
- The notation `3p^(4)` indicates that we are dealing with electrons in the p subshell of the third energy level (or shell).
- The principal quantum number (n) is 3, which corresponds to the third shell.

2. **Identifying the Shell and Subshell**:
- The principal quantum number (n = 3) indicates that these electrons are in the third shell.
- The letter 'p' indicates that we are looking at the p subshell. The p subshell corresponds to an azimuthal quantum number (l) of 1.

3. **Determining the Electron Configuration**:
- The notation `p^(4)` means there are 4 electrons in the p subshell.
- The p subshell can hold a maximum of 6 electrons (since it has 3 orbitals, each capable of holding 2 electrons).

4. **Evaluating the Options**:
- **Option A**: "Electrons are in the m shell." - This is true because n = 3 corresponds to the m shell.
- **Option B**: "Electrons are in l = 2 subshell." - This is false because l = 2 corresponds to the d subshell, not the p subshell.
- **Option C**: "Electrons are necessarily in an excited state." - This is false; the electrons could be in their ground state or excited state, but we cannot conclude they are necessarily excited.
- **Option D**: "They have principal quantum number 4." - This is false; the principal quantum number is 3, not 4.

5. **Conclusion**:
- The only true statement concerning the electrons specified by the notation `3p^(4)` is that "Electrons are in the m shell."

### Final Answer:
The correct statement is: **Electrons are in the m shell.**