Q: A laser emits light with a wavelength of $640.0\ \mathrm{nm}$. What is the frequency of this light? (Speed of light $c = 3.00 \times 10^8\ \mathrm{m/s}$)

$4.69 \times 10^{14}\ \mathrm{s}^{-1}$

Question 1

Which of the following statements best explains why the frequency of wave (b) in the first image is greater than that of wave (a)?

Accepted Answer

Wave (b) has a shorter wavelength, and since frequency and wavelength are inversely related by $v = \frac{c}{\lambda}$, its frequency is higher.

Question 2

A laser emits light with a wavelength of $640.0\ \mathrm{nm}$. What is the frequency of this light? (Speed of light $c = 3.00 	imes 10^8\ \mathrm{m/s}$)

Accepted Answer

$4.69 	imes 10^{14}\ \mathrm{s}^{-1}$

Question 3

Which region of the electromagnetic spectrum has the shortest wavelength and the highest energy?

Accepted Answer

Gamma rays

Question 4

The photoelectric effect provided evidence that light:

Accepted Answer

Behaves as particles called photons, each with energy $E = hv$

Question 5

Which equation correctly relates the energy of a photon to its wavelength?

Accepted Answer

$E = \frac{hc}{\lambda}$

Question 6

A student observes the emission spectrum of hydrogen and sees only specific lines rather than a continuous spectrum. What does this observation indicate about the energy levels in a hydrogen atom?

Accepted Answer

The energy levels are quantized, and electrons can only occupy specific energy states.

Question 7

According to the Bohr model, what happens when an electron in a hydrogen atom transitions from $n=3$ to $n=2$?

Accepted Answer

A photon is emitted and the atom releases energy.

Question 8

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number ($l$)

Question 9

How many possible values of $m_l$ are there for a $d$ orbital?

Accepted Answer

5

Question 10

Which of the following electron configurations represents a phosphorus atom in its ground state?

Accepted Answer

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

Question 11

Which of the following is a correct condensed electron configuration for potassium ($K$)?

Accepted Answer

$[Ar]4s^1$

Question 12

Which rule states that electrons fill degenerate orbitals singly with parallel spins before pairing up?

Accepted Answer

Hund's Rule

Question 13

How many unpaired electrons are present in a nitrogen atom ($1s^2 2s^2 2p^3$)?

Accepted Answer

3

Question 14

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

Accepted Answer

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

Question 15

Which element has the electron configuration $[Ar]4s^2 3d^5$?

Accepted Answer

Manganese (Mn)

Question 16

Why is the electron configuration of chromium ($Cr$) $[Ar]4s^1 3d^5$ instead of $[Ar]4s^2 3d^4$?

Accepted Answer

Because a half-filled $d$ subshell ($d^5$) is particularly stable due to exchange energy.

Question 17

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

Accepted Answer

Magnetic quantum number ($m_l$)

Question 18

How many total orbitals are present in the $n=3$ shell?

Accepted Answer

9

Question 19

Which of the following best describes the difference between a node and an antinode in an atomic orbital?

Accepted Answer

A node is a region of zero electron probability, while an antinode is a region of maximum probability.

Chapter 6: Electronic Structure of Atoms – Study Notes

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