Question 1

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

Accepted Answer

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

Question 2

Which rule correctly describes the possible values for the magnetic quantum number $m_l$?

Accepted Answer

$m_l$ can be any integer from $-l$ to $+l$

Question 3

What is the correct electron configuration for technetium (Tc), atomic number 43?

Accepted Answer

$[Kr] \ 5s^2 \ 4d^5$

Question 4

Which of the following is the correct electron configuration for the $Fe^{2+}$ ion?

Accepted Answer

$[Ar] \ 3d^6$

Question 5

A photon has a frequency of $3.44 	imes 10^{15}$ Hz. What is its wavelength in meters?

Accepted Answer

$8.72 	imes 10^{-8}$ m

Question 6

What is the energy (in Joules) of a photon with a frequency of $3.44 	imes 10^{15}$ Hz?

Accepted Answer

$2.28 	imes 10^{-18}$ J

Question 7

An electron (mass $9.11 	imes 10^{-31}$ kg) is moving at $2.56 	imes 10^6$ m/s. What is its de Broglie wavelength?

Accepted Answer

$2.82 	imes 10^{-10}$ m

Question 8

An electron in a hydrogen atom transitions from $n=4$ to $n=2$. What is the wavelength (in nm) of the photon emitted?

Accepted Answer

$486$ nm

Question 9

Which statement best explains why the $n=4$ to $n=2$ transition in hydrogen emits a photon?

Accepted Answer

The electron loses energy, which is released as a photon.

Question 10

Calculate the longest wavelength of light that can be emitted from a $He^+$ ion when the electron falls to $n=2$ from a higher energy level.

Accepted Answer

$164$ nm

Question 11

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Azimuthal quantum number $l$

Question 12

Which of the following transitions in a hydrogen atom would result in the emission of the highest energy photon?

Accepted Answer

$n=3$ to $n=1$

Question 13

Which of the following is a correct statement about the spin quantum number $m_s$?

Accepted Answer

$m_s$ can be $+\frac{1}{2}$ or $-\frac{1}{2}$

Question 14

Which principle states that no two electrons in an atom can have the same set of four quantum numbers?

Accepted Answer

Pauli Exclusion Principle

Question 15

If a photon is absorbed by an atom, what happens to the electron?

Accepted Answer

It moves to a higher energy level.

Question 16

Which formula is used to calculate the energy of a photon?

Accepted Answer

$E = h 
u$

Question 17

Which formula is used to calculate the wavelength of a moving electron?

Accepted Answer

$\lambda = \frac{h}{mv}$

Question 18

Which quantum number is responsible for the orientation of an orbital in space?

Accepted Answer

Magnetic quantum number $m_l$

Question 19

Which of the following best describes the relationship between energy and wavelength for electromagnetic radiation?

Accepted Answer

Energy is inversely proportional to wavelength.

Quantum Numbers, Electron Configuration, and Photons: Study Notes for General Chemistry

Study Guide - Practice Questions