Question 1

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

Accepted Answer

They are inversely proportional; as wavelength increases, frequency decreases.

Question 2

A photon of ultraviolet light has a wavelength of $$2.50 	imes 10$$^{-7}$$ m. What is its frequency ($$
u$$)? (Speed of light c = 3.00$$ 	imes $$10^8 m/s)$$

Accepted Answer

$$1.20 	imes 10$$^{15}$$ Hz$

Question 3

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

Accepted Answer

Gamma rays

Question 4

The energy of a photon is given by $$E = h
u. If $$the frequency of a photon is doubled, what happens to its energy?

Accepted Answer

The energy is doubled.

Question 5

Which of the following best describes the photoelectric effect?

Accepted Answer

The ejection of electrons from a metal surface when exposed to light of sufficient frequency.

Question 6

An electron in a hydrogen atom transitions from $$n=4 to$$ $$n=2. $$Which of the following statements is true?

Accepted Answer

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

Question 7

Which equation would you use to calculate the wavelength of light emitted when an electron in a hydrogen atom transitions from a higher energy level $$n_2 to a $$lower energy level $$n_1$$?

Accepted Answer

$$\frac{1}{\lambda} = R_H \left( \frac{1}{n_1$^2} - \frac{1}{n_2$^2} \right)$$

Question 8

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

Accepted Answer

It only accurately describes atoms with one electron.

Question 9

According to the Heisenberg Uncertainty Principle, which of the following is true?

Accepted Answer

The more precisely the position of an electron is known, the less precisely its momentum can be known.

Question 10

Which quantum number determines the shape of an orbital?

Accepted Answer

Angular momentum quantum number ($$l)$$

Question 11

Which of the following electron configurations represents a ground state atom of nitrogen (atomic number 7)?

Accepted Answer

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

Question 12

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 13

Which of the following best explains the trend in atomic radius across a period from left to right?

Accepted Answer

Atomic radius decreases due to increasing effective nuclear charge.

Question 14

Which of the following ions is isoelectronic with neon ($$Ne$$)?

Accepted Answer

$$Na^+$$

Question 15

Which element would you expect to have the highest first ionization energy?

Accepted Answer

Neon ($$Ne)$$

Question 16

Which of the following statements about electron affinity is correct?

Accepted Answer

Electron affinity generally becomes more negative across a period from left to right.

Question 17

Which of the following best describes a paramagnetic atom?

Accepted Answer

An atom with one or more unpaired electrons.

Question 18

Which of the following elements is a metalloid and commonly used as a semiconductor in electronics?

Accepted Answer

Silicon ($$Si)$$

Question 19

Which of the following best explains why transition metals often have anomalous electron configurations?

Accepted Answer

The $$s$$ and $$d$$ subshells are very close in energy, so electrons may fill to achieve greater stability.

Question 20

Which of the following statements about effective nuclear charge ($$Z_{eff}) is $$correct?

Accepted Answer

$$Z_{eff}$$ increases across a period due to increasing nuclear charge and incomplete shielding.

Atomic Theory, Electromagnetic Spectrum, Quantum Mechanics, and Periodic Trends Study Guide – Step-by-Step Guidance

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