Q: A photon has a wavelength of $4.00 \times 10^{-7}\ \mathrm{m}$. What is its energy? ($h = 6.626 \times 10^{-34}\ \mathrm{J\cdot s}$, $c = 3.00 \times 10^8\ \mathrm{m/s}$)

$4.97 \times 10^{-19}\ \mathrm{J}$

Q: A sodium atom emits light with a wavelength of $589\ \mathrm{nm}$ during a transition. What is the frequency of this light? ($c = 3.00 \times 10^8\ \mathrm{m/s}$)

$5.09 \times 10^{14}\ \mathrm{Hz}$

Q: Which of the following best explains the existence of exceptions to the general trend in electron configurations (such as chromium and copper)?

Half-filled and fully filled $d$ subshells provide extra stability to the atom.

Q: Which of the following is the correct set of quantum numbers for the last electron added to a phosphorus ($\mathrm{P}$) atom in its ground state?

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

Q: Which of the following best describes the periodic law?

The properties of elements are periodic functions of their atomic numbers.

Question 1

Which of the following correctly describes the relationship between wavelength ($\lambda$) and momentum ($p$) for a particle, according to de Broglie's hypothesis?

Accepted Answer

$\lambda = \dfrac{h}{p}$

Question 2

Which set of quantum numbers is NOT allowed for an electron in an atom?

Accepted Answer

$n = 2, \ l = 2, \ m_l = 0, \ m_s = +\dfrac{1}{2}$

Question 3

Which element has the highest first ionization energy?

Accepted Answer

Neon ($\mathrm{Ne}$)

Question 4

Which of the following statements about atomic radius is correct?

Accepted Answer

Atomic radius decreases across a period from left to right due to increasing nuclear charge.

Question 5

Which of the following electron configurations represents a transition metal in its ground state?

Accepted Answer

$[\mathrm{Ar}]\ 4s^2\ 3d^6$

Question 6

A photon has a wavelength of $4.00 	imes 10^{-7}\ \mathrm{m}$. What is its energy? ($h = 6.626 	imes 10^{-34}\ \mathrm{J\cdot s}$, $c = 3.00 	imes 10^8\ \mathrm{m/s}$)

Accepted Answer

$4.97 	imes 10^{-19}\ \mathrm{J}$

Question 7

Which of the following best explains why the ionization energy of oxygen is less than that of nitrogen, despite oxygen being to the right of nitrogen in the periodic table?

Accepted Answer

Electron-electron repulsion in the doubly occupied $2p$ orbital of oxygen makes it easier to remove an electron.

Question 8

Which of the following elements is in the same period as phosphorus ($\mathrm{P}$) and in the same group as magnesium ($\mathrm{Mg}$)?

Question 9

Which block of the periodic table contains elements with their last electron entering a $d$ orbital?

Accepted Answer

d-block

Question 10

Which of the following is the correct electron configuration for a chloride ion ($\mathrm{Cl}^-$)?

Accepted Answer

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

Question 11

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Azimuthal quantum number ($l$)

Question 12

Which of the following best describes the trend in ionization energy as you move down a group in the periodic table?

Accepted Answer

Ionization energy decreases due to increased atomic radius and electron shielding.

Question 13

Which of the following elements has the largest atomic radius?

Accepted Answer

Potassium ($\mathrm{K}$)

Question 14

Which of the following is a correct statement about valence electrons?

Accepted Answer

Valence electrons are the electrons in the outermost shell of an atom and are involved in chemical bonding.

Question 15

Which of the following is the correct order of increasing energy for the orbitals within a given shell (same $n$ value)?

Accepted Answer

$s < p < d < f$

Question 16

A sodium atom emits light with a wavelength of $589\ \mathrm{nm}$ during a transition. What is the frequency of this light? ($c = 3.00 	imes 10^8\ \mathrm{m/s}$)

Accepted Answer

$5.09 	imes 10^{14}\ \mathrm{Hz}$

Question 17

Which of the following best explains the existence of exceptions to the general trend in electron configurations (such as chromium and copper)?

Accepted Answer

Half-filled and fully filled $d$ subshells provide extra stability to the atom.

Question 18

Which of the following is the correct set of quantum numbers for the last electron added to a phosphorus ($\mathrm{P}$) atom in its ground state?

Accepted Answer

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

Question 19

Which of the following best describes the periodic law?

Accepted Answer

The properties of elements are periodic functions of their atomic numbers.

Question 20

Which of the following statements about the quantum mechanical model of the atom is correct?

Accepted Answer

It describes electrons as occupying orbitals, which are regions of space with a high probability of finding an electron.

Atomic Structure, Quantum Mechanics, and Periodic Trends: Study Notes for General Chemistry

Study Guide - Practice Questions