Q: A photon has a wavelength of $500\ \mathrm{nm}$. What is its energy in joules? (Use $h = 6.626 \times 10^{-34}\ \mathrm{J\cdot s}$ and $c = 3.00 \times 10^8\ \mathrm{m/s}$)

$3.98 \times 10^{-19}\ \mathrm{J}$

Q: Which of the following statements about the Heisenberg Uncertainty Principle is correct?

The more accurately we know the position of an electron, the less accurately we know its momentum.

Q: Which of the following best describes the difference between a continuous spectrum and a line spectrum?

A continuous spectrum contains all wavelengths within a range, while a line spectrum contains only specific wavelengths.

Q: Which of the following best describes the trend in electronegativity across a period and down a group?

Electronegativity decreases down a group and increases across a period.

Question 1

Which of the following best explains why the atomic radius decreases across a period from left to right in the periodic table?

Accepted Answer

The effective nuclear charge increases, pulling the valence electrons closer to the nucleus.

Question 2

A photon has a wavelength of $500\ \mathrm{nm}$. What is its energy in joules? (Use $h = 6.626 	imes 10^{-34}\ \mathrm{J\cdot s}$ and $c = 3.00 	imes 10^8\ \mathrm{m/s}$)

Accepted Answer

$3.98 	imes 10^{-19}\ \mathrm{J}$

Question 3

Which quantum numbers are needed to uniquely describe an electron in an atom?

Accepted Answer

Principal quantum number ($n$), angular-momentum quantum number ($\ell$), magnetic quantum number ($m_\ell$), and spin quantum number ($m_s$)

Question 4

Which of the following statements about the photoelectric effect is correct?

Accepted Answer

Electrons are emitted only if the frequency of the incident light is above a certain threshold, regardless of intensity.

Question 5

What is the maximum number of electrons that can occupy the $n=3$ shell of an atom?

Accepted Answer

18

Question 6

Which element has the following ground state electron configuration: $[Ne]\ 3s^2\ 3p^3$?

Accepted Answer

Phosphorus (P)

Question 7

Which of the following ions is isoelectronic with argon ($\mathrm{Ar}$)?

Accepted Answer

$\mathrm{K}^+$

Question 8

Which of the following best describes Hund’s rule?

Accepted Answer

Electrons occupy degenerate orbitals singly before pairing.

Question 9

Which of the following transitions in a hydrogen atom will emit the highest energy photon?

Accepted Answer

$n=4 \rightarrow n=2$

Question 10

Which of the following statements about ionic radii is correct?

Accepted Answer

Cations are smaller and anions are larger than their parent atoms.

Question 11

Which of the following best explains why the lattice energy of $\mathrm{MgO}$ is much higher than that of $\mathrm{NaF}$, even though their ionic radii are similar?

Accepted Answer

The charges on $\mathrm{Mg}^{2+}$ and $\mathrm{O}^{2-}$ are higher, leading to a stronger electrostatic attraction.

Question 12

Which of the following is the correct order of increasing ionization energy for the elements Na, Mg, and Al?

Accepted Answer

Na < Mg < Al

Question 13

Which of the following statements about the Heisenberg Uncertainty Principle is correct?

Accepted Answer

The more accurately we know the position of an electron, the less accurately we know its momentum.

Question 14

Which of the following best describes the difference between a continuous spectrum and a line spectrum?

Accepted Answer

A continuous spectrum contains all wavelengths within a range, while a line spectrum contains only specific wavelengths.

Question 15

Which of the following electron configurations represents an excited state of a carbon atom?

Accepted Answer

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

Question 16

Which of the following best describes the trend in electronegativity across a period and down a group?

Accepted Answer

Electronegativity decreases down a group and increases across a period.

Question 17

Which of the following is the correct condensed electron configuration for the $\mathrm{Fe}^{3+}$ ion?

Accepted Answer

$[Ar]\ 3d^5$

Question 18

Which of the following best explains why ionic compounds have high melting points?

Accepted Answer

They are held together by strong electrostatic attractions between cations and anions in a crystal lattice.

Question 19

Which of the following statements about the Pauli Exclusion Principle is correct?

Accepted Answer

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

Periodicity, Electronic Structure, and Ionic Bonding: Study Notes for General Chemistry

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