Question 1

Which quantum number primarily determines the energy level of an electron in an atom?

Accepted Answer

The principal quantum number $n$

Question 2

What is the maximum number of electrons that can occupy a single orbital?

Accepted Answer

Two

Question 3

Which of the following sets of quantum numbers is NOT allowed for an electron in an atom?

Accepted Answer

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

Question 4

Which orbital type is spherical in shape?

Accepted Answer

s orbital

Question 5

According to the Pauli Exclusion Principle, how many electrons in an atom can have the same set of four quantum numbers?

Accepted Answer

None

Question 6

Which of the following electron configurations represents the ground state of fluorine (atomic number 9)?

Accepted Answer

$1s^2\ 2s^2\ 2p^5$

Question 7

Which statement best explains why the atomic radius decreases across a period from left to right?

Accepted Answer

The nuclear charge increases, pulling electrons closer

Question 8

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

Accepted Answer

$1s^2\ 2s^2\ 2p^6\ 3s^2\ 3p^6\ 3d^6$

Question 9

Which element is expected to have the highest first ionization energy?

Accepted Answer

Fluorine ($F$)

Question 10

In an isoelectronic series of ions with 10 electrons, which ion will have the smallest radius?

Accepted Answer

$Na^{+}$

Question 11

Which of the following best describes the electron configuration anomaly observed in chromium ($Cr$)?

Accepted Answer

Chromium has a half-filled $3d$ orbital and a half-filled $4s$ orbital

Question 12

Which quantum number defines the shape of an orbital?

Accepted Answer

Azimuthal quantum number $l$

Question 13

What is the condensed electron configuration for potassium ($K$, atomic number 19)?

Accepted Answer

$[Ar]\ 4s^1$

Question 14

Which of the following statements about degenerate orbitals is correct?

Accepted Answer

Degenerate orbitals have the same energy

Question 15

Which of the following ions is isoelectronic with neon ($Ne$)?

Accepted Answer

$Na^{+}$

Question 16

Which quantum number describes the orientation of an orbital in space?

Accepted Answer

Magnetic quantum number $m_l$

Question 17

Which of the following best explains why anions are larger than their parent atoms?

Accepted Answer

Anions have more electrons, increasing electron-electron repulsion

Question 18

Which of the following elements is a lanthanide?

Accepted Answer

Cerium ($Ce$)

Question 19

What is the electron configuration for the fluoride ion ($F^{-}$)?

Accepted Answer

$1s^2\ 2s^2\ 2p^6$

Question 20

Which of the following statements about electron affinity is correct?

Accepted Answer

Electron affinity is typically exothermic for most elements

Electronic Structure of Atoms: Quantum Numbers, Orbitals, and Electron Configurations

Study Guide - Practice Questions