Question 1

Which of the following is the correct ground state electron configuration for a neutral vanadium atom ($$Z=23$$)?

Accepted Answer

$$[Ar] 4s^2$ 3d^3$

Question 2

Which of the following elements is expected to be paramagnetic in its ground state?

Accepted Answer

Nitrogen ($$Z=7)$$

Question 3

What is the condensed electron configuration for the aluminum atom ($$Z=13$$)?

Accepted Answer

$$[Ne] 3s^2$ 3p^1$

Question 4

Which of the following ions has the same electron configuration as neon?

Accepted Answer

$$\mathrm{F}^-$$

Question 5

Which of the following best explains why chromium ($$Z=24) $$has the electron configuration $$[Ar] 4s^1$ 3d^5$ instead of $$[Ar] $$4s^2$$ $$3d^4$$?

Accepted Answer

A half-filled $$d$$ subshell is more stable due to exchange energy and symmetry.

Question 6

Which set of quantum numbers is NOT allowed for an electron in a $$3d$$ orbital?

Accepted Answer

$$n=3,\ l=2,\ m_l=3,\ m_s=+\frac{1}{2}$$

Question 7

A nitride ion ($$\mathrm{N}^{3-}) is$$:

Accepted Answer

Diamagnetic, because all electrons are paired.

Question 8

Which of the following correctly describes the order in which orbitals are filled according to the Aufbau principle?

Accepted Answer

$$1s \rightarrow 2s \rightarrow 2p \rightarrow 3s \rightarrow 3p \rightarrow 4s \rightarrow 3d$$

Question 9

Which of the following ions is isoelectronic with argon ($$Z=18$$)?

Accepted Answer

$$\mathrm{Cl}^-$$

Question 10

When forming a cation, from which orbital are electrons removed first?

Accepted Answer

The orbital with the highest principal quantum number $$n$$

Question 11

Which of the following statements about the periodic law is correct?

Accepted Answer

Elements in the same group have similar chemical properties due to similar valence electron configurations.

Question 12

Which of the following is the correct condensed electron configuration for the zinc ion $$\mathrm{Zn}^{2+}$$ ($$Z=30$$)?

Accepted Answer

$$[Ar] 3d$$^{10}$$

Question 13

Which of the following best describes a diamagnetic atom?

Accepted Answer

All electrons are paired in its electron configuration.

Question 14

Which of the following is the correct set of quantum numbers for the last electron added to an oxygen atom ($$Z=8) in $$its ground state?

Accepted Answer

$$n=2,\ l=1,\ m_l=0,\ m_s=-\frac{1}{2}$$

Question 15

Which of the following elements has an electron configuration that ends with $$4d^{10}$$ $$5s^1$$ due to an exception to the expected filling order?

Accepted Answer

Silver ($$Z=47)$$

Question 16

Which of the following best explains why the $$4s$$ orbital is filled before the $$3d$$ orbital in the electron configuration of potassium ($$Z=19$$)?

Accepted Answer

The $$4s$$ orbital is lower in energy than the $$3d$$ orbital for potassium.

Question 17

Which of the following is the correct electron configuration for the $$\mathrm{Fe}^{3+}$$ ion ($$Z=26$$)?

Accepted Answer

$$[Ar] 3d^5$

Question 18

Which of the following statements about quantum numbers is correct?

Accepted Answer

The magnetic quantum number $$m_l$$ can have values from $$-l to$$ $$+l in $$integer steps.

Question 19

A hospital is using sodium vapor lamps for lighting. Which block of the periodic table does sodium belong to, and what is its condensed electron configuration?

Accepted Answer

S-block; $$[Ne] 3s^1$

Electron Configuration and Quantum Numbers: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards