Question 1

Which of the following statements best describes the relationship between wavelength ($$\lambda) $$and frequency ($$
u) of $$electromagnetic radiation?

Accepted Answer

As wavelength increases, frequency decreases.

Question 2

A sodium vapor streetlamp emits light at a wavelength of 589 nm. What is the frequency ($$
u) of $$this radiation? (Speed of light $$c = 3.00 	imes 10^8$ m/s)

Accepted Answer

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

Question 3

Which experiment provided the first evidence for the existence of the electron?

Accepted Answer

The cathode ray tube experiment

Question 4

According to Planck's theory, the energy of a photon is quantized. Which equation correctly expresses the energy of a photon?

Accepted Answer

$$E = h
u$$

Question 5

A laser pointer emits light at a wavelength of 650 nm. What is the energy of a single photon from the laser pointer? ($$h = 6.626 	imes 10$$^{-34}$$ J·s, c = 3.00$$ 	imes $$10^8 m/s)$$

Accepted Answer

$$3.06 	imes 10$$^{-19}$$ J

Question 6

Which of the following best explains why hydrogen emits a line spectrum rather than a continuous spectrum?

Accepted Answer

Electrons in hydrogen can only occupy specific, quantized energy levels.

Question 7

According to the Bohr model, what happens when an electron in a hydrogen atom transitions from $$n=5 to$$ $$n=2$$?

Accepted Answer

The atom emits a photon and the electron moves to a lower energy level.

Question 8

Which of the following is a limitation of the Bohr model of the atom?

Accepted Answer

It only works for one-electron systems.

Question 9

The de Broglie wavelength ($$\lambda) of a $$particle is given by which equation?

Accepted Answer

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

Question 10

Which principle states that it is impossible to know both the exact position and momentum of an electron at the same time?

Accepted Answer

Heisenberg uncertainty principle

Question 11

Which quantum number defines the shape of an atomic orbital?

Accepted Answer

Azimuthal (angular momentum) quantum number ($$\ell)$$

Question 12

How many different orientations are possible for $$d$$ orbitals in a given shell?

Accepted Answer

5

Question 13

Which set of quantum numbers is valid for an electron in an atom?

Accepted Answer

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

Question 14

Which rule explains why electrons fill degenerate orbitals singly before pairing up?

Accepted Answer

Hund's rule

Question 15

What is the condensed electron configuration for silicon (Si, $$Z=14$$)?

Accepted Answer

$$[Ne] 3s^2$ 3p^2$

Question 16

For the $$n=3$$ shell, how many total orbitals are present?

Accepted Answer

9

Question 17

Which of the following best explains why the $$2s$$ orbital is lower in energy than the $$2p$$ orbital in multi-electron atoms?

Accepted Answer

The $$2s$$ orbital has more radial nodes and penetrates closer to the nucleus.

Question 18

When forming a cation from a transition metal, which electrons are removed first?

Accepted Answer

Electrons from the $$s$$ orbital with the highest principal quantum number

Question 19

Which of the following is a real-world application of the wave nature of electrons?

Accepted Answer

Scanning electron microscopy

Question 20

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

Accepted Answer

Pauli exclusion principle

The Quantum Mechanical Model of the Atom: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards