Question 1

Which quantum number is responsible for describing the orientation of an electron's spin, and what are its possible values?

Accepted Answer

The spin quantum number, $m_s$, with values $+\frac{1}{2}$ and $-\frac{1}{2}$

Question 2

According to the Pauli Exclusion Principle, which of the following statements is correct?

Accepted Answer

No two electrons in the same atom can have the same set of four quantum numbers.

Question 3

How many electrons can be accommodated in the $n=3$ shell of an atom?

Accepted Answer

$18$

Question 4

Which of the following correctly describes the order of filling for the $3d$ and $4s$ orbitals in transition metals?

Accepted Answer

$4s$ fills before $3d$

Question 5

What is the maximum number of electrons that can occupy the $4f$ subshell?

Accepted Answer

$14$

Question 6

Which of the following electron configurations represents a paramagnetic atom?

Accepted Answer

$1s^2 2s^2 2p^4$

Question 7

For a multi-electron atom, which factor primarily determines the energy of an orbital?

Accepted Answer

Both the principal quantum number $n$ and the angular momentum quantum number $l$

Question 8

Which of the following is the correct electron configuration for a neutral nickel (Ni) atom?

Accepted Answer

$[Ar] 4s^2 3d^8$

Question 9

Which rule explains why electrons fill degenerate orbitals singly before pairing up?

Accepted Answer

Hund's Rule

Question 10

What is the electron configuration for the Fe$^{2+}$ ion?

Accepted Answer

$[Ar] 3d^6$

Question 11

Which of the following elements is filling the $5f$ subshell?

Accepted Answer

Actinides

Question 12

Which pair of elements has the same ground-state valence shell configuration of $ns^2 np^2$?

Accepted Answer

Ge and Si

Question 13

How many unpaired electrons are found in the ground state electron configuration of selenium (Se)?

Accepted Answer

2

Question 14

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

Accepted Answer

From the $ns$ orbital

Question 15

Which of the following ions is paramagnetic?

Accepted Answer

Fe$^{3+}$

Question 16

What is the total number of electrons that can be accommodated in the $n=4$ shell?

Accepted Answer

$32$

Question 17

Which of the following best explains why the $2p$ subshell is higher in energy than the $2s$ subshell in a multi-electron atom?

Accepted Answer

The $2p$ electrons experience more shielding from inner electrons

Question 18

Which of the following is an example of an irregular electron configuration due to extra stability of a half-filled subshell?

Accepted Answer

Cr: $[Ar] 4s^1 3d^5$

Question 19

Which of the following statements about paramagnetism and diamagnetism is correct?

Accepted Answer

Paramagnetic substances have unpaired electrons

Question 20

A hospital MRI machine uses a strong magnetic field. Which type of atom or ion would be most affected by this field?

Accepted Answer

A paramagnetic atom

Quantum Numbers, Electron Configurations, and Magnetism in Atoms

Study Guide - Practice Questions