Q: A dental hygienist uses x-rays with $\lambda = 0.50\ \text{\AA}$ to take radiographs. What is the frequency of these x-rays? (Speed of light $c = 3.00 \times 10^8\ \text{m/s}$)

$6.0 \times 10^{18}\ \text{s}^{-1}$

Question 1

Which atomic model first introduced the concept of quantized energy levels for electrons in the atom?

Accepted Answer

Bohr's Model of the Hydrogen Atom

Question 2

Which property of electromagnetic radiation is directly related to its energy?

Accepted Answer

Frequency ($
u$)

Question 3

A dental hygienist uses x-rays with $\lambda = 0.50\ 	ext{\AA}$ to take radiographs. What is the frequency of these x-rays? (Speed of light $c = 3.00 	imes 10^8\ 	ext{m/s}$)

Accepted Answer

$6.0 	imes 10^{18}\ 	ext{s}^{-1}$

Question 4

Which statement about the photoelectric effect is correct?

Accepted Answer

Electrons are emitted only when the frequency of light exceeds a threshold value, regardless of intensity.

Question 5

What is the formula for the energy of a photon in terms of its wavelength?

Accepted Answer

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

Question 6

Which of the following best describes a line spectrum?

Accepted Answer

It displays only a few lines, each corresponding to discrete wavelengths.

Question 7

According to the Bohr model, what happens when an electron transitions from a higher energy level ($n$) to a lower energy level?

Accepted Answer

A photon is emitted.

Question 8

Calculate the energy change ($\Delta E$) for an electron transition in hydrogen from $n_i = 3$ to $n_f = 2$ using $\Delta E = -2.179 	imes 10^{-18} \left( \dfrac{1}{n_f^2} - \dfrac{1}{n_i^2} ight)$ J.

Accepted Answer

$-4.57 	imes 10^{-19}$ J

Question 9

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number ($\ell$)

Question 10

Which combination of quantum numbers is NOT allowed?

Accepted Answer

$n=1,\ \ell=1,\ m_\ell=0,\ m_s=+\frac{1}{2}$

Question 11

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 12

What is the maximum number of electrons that can occupy a $d$ sublevel?

Accepted Answer

10

Question 13

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

Accepted Answer

Hund's Rule

Question 14

Which element has the largest atomic radius?

Accepted Answer

Sodium (Na)

Question 15

What is the basis for the transmission of nerve signals involving Na$^+$ and K$^+$ ions?

Accepted Answer

The difference in their ionic sizes

Question 16

Which of the following is true about the ionization energy trend in the periodic table?

Accepted Answer

Ionization energy increases across a period.

Question 17

Which of the following elements is most likely to have the highest electron affinity?

Accepted Answer

Chlorine (Cl)

Question 18

According to de Broglie's equation, what happens to the wavelength of a particle as its mass increases?

Accepted Answer

The wavelength decreases.

Question 19

Which statement best describes the Heisenberg uncertainty principle?

Accepted Answer

It is impossible to know both the position and momentum of a particle simultaneously with absolute certainty.

Chapter 3: Electronic Structure of the Atom – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards