Q: A photon of ultraviolet light has a wavelength of $$200\ \mathrm{nm}. $$Calculate its energy in joules. ($$h = 6.626 \times 10$$^{-34}$$\ \mathrm{J \cdot s}$$, $$c = 3.00 \times 10^8$\ \mathrm{m/s})$$

$$9.94 \times 10$$^{-19}$$\ \mathrm{J}$$

Question 1

Which of the following best describes the relationship between wavelength ($$\lambda$$), frequency ($$
u$$), and the speed of light ($$c) $$for electromagnetic radiation?

Accepted Answer

$$c = \lambda 	imes 
u$$

Question 2

A photon of ultraviolet light has a wavelength of $$200\ \mathrm{nm}. $$Calculate its energy in joules. ($$h = 6.626 	imes 10$$^{-34}$$\ \mathrm{J \cdot s}$$, $$c = 3.00 	imes 10^8$\ \mathrm{m/s})$$

Accepted Answer

$$9.94 	imes 10$$^{-19}$$\ \mathrm{J}$$

Question 3

Which phenomenon provides evidence for the wave nature of light?

Accepted Answer

Diffraction and interference patterns

Question 4

In the photoelectric effect, what happens when the frequency of incident light is below the threshold frequency for a metal, regardless of intensity?

Accepted Answer

No electrons are emitted

Question 5

Which equation correctly relates the energy of a photon ($$E) to $$its wavelength ($$\lambda$$)?

Accepted Answer

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

Question 6

Which region of the electromagnetic spectrum has wavelengths on the order of atomic sizes (about $$0.1\ \mathrm{nm}$$)?

Accepted Answer

X-rays

Question 7

Why does atomic radius decrease across a period (row) in the periodic table?

Accepted Answer

Effective nuclear charge increases, pulling electrons closer

Question 8

Which of the following transitions in a hydrogen atom would release the largest quantum of energy?

Accepted Answer

$$n = 3 \rightarrow n = 1$$

Question 9

What is the effective nuclear charge ($$Z_{	ext{eff}}) $$experienced by a valence electron in a nitrogen atom ($$Z = 7$$)?

Accepted Answer

$$Z_{	ext{eff}} = 5$$

Question 10

Which of the following best explains why the ionization energy decreases down a group in the periodic table?

Accepted Answer

Valence electrons are farther from the nucleus and experience more shielding

Question 11

Which of the following is true about the emission spectrum of an element?

Accepted Answer

It contains only specific wavelengths unique to the element

Question 12

Which of the following best describes the Heisenberg Uncertainty Principle?

Accepted Answer

It is impossible to know both the exact position and momentum of an electron simultaneously

Question 13

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

Accepted Answer

$$\mathrm{Na}^+$$

Question 14

Which of the following best explains why the third ionization energy of magnesium is much higher than the first and second?

Accepted Answer

The third electron is removed from a core shell, which is much closer to the nucleus

Question 15

Which of the following is the correct noble gas electron configuration for oxygen?

Accepted Answer

[He] $$2s^2$$ $$2p^4$$

Question 16

Which of the following best describes the difference between a continuous spectrum and an atomic emission spectrum?

Accepted Answer

A continuous spectrum contains all wavelengths, while an atomic emission spectrum contains only specific wavelengths

Question 17

Which of the following best explains why the atomic radius of sodium ($$\mathrm{Na}) is $$larger than that of lithium ($$\mathrm{Li}$$)?

Accepted Answer

Sodium has more energy levels, so its valence electrons are farther from the nucleus

Question 18

Which of the following best describes the effect of increasing the intensity of light in the photoelectric effect (above the threshold frequency)?

Accepted Answer

More electrons are emitted

Question 19

Which of the following best describes the dual nature of light?

Accepted Answer

Light exhibits both wave-like and particle-like properties

Question 20

Which of the following best explains why the emission spectrum of hydrogen contains only certain wavelengths?

Accepted Answer

Electrons in hydrogen can only occupy specific energy levels, so only certain transitions are possible

Quantum Mechanics and Electron Configurations: The Nature of Light and Atomic Structure

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