### All Physical Chemistry Resources

## Example Questions

### Example Question #1 : Principles Of Quantum Mechanics

How many sublevels are there with n = 2 in an atom?

**Possible Answers:**

18

12

16

20

9

**Correct answer:**

18

The types of subshells, from smallest to largest, are as follows: s, p, d, and f. These four subshells correspond respectively to the following quantum numbers: 0, 1, 2, and 3. The total number of orbitals in an atom with n = 3 is 3^{2} or 9: one 3s , three 3p and five 3d. Each orbital can hold a maximum of 2 electrons. Therefore, the maximum number of electrons possible is 2 x 9 = 18.

### Example Question #76 : Physical Chemistry

What is the maximum number of electrons possible with n = 4 in an atom?

**Possible Answers:**

**Correct answer:**

The types of subshells, from smallest to largest, are as follows: *s, p, d,* and *f*. These four subshells correspond respectively to the following quantum numbers: 0, 1, 2, and 3. The total number of orbitals in an atom with n = 4 is 4^{2} or 16: one *4s* , three *4p* , five *4d* and seven *4f*. Each orbital can hold a maximum of 2 electrons. Therefore, the maximum number of electrons possible is 32.

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