Q: A sodium streetlight emits yellow light with a wavelength of $$589\ \text{nm}. $$What is the frequency of this light? (Speed of light $$c = 2.998 \times 10^8$\ \text{m/s})$$

$$5.09 \times 10$$^{14}$$\ \text{Hz}$$

Question 1

Which of the following statements best explains why the atomic radius increases as you move down a group in the periodic table?

Accepted Answer

Electrons are added to higher principal quantum number shells, increasing the distance from the nucleus.

Question 2

A sodium streetlight emits yellow light with a wavelength of $$589\ 	ext{nm}. $$What is the frequency of this light? (Speed of light $$c = 2.998 	imes 10^8$\ 	ext{m/s})$$

Accepted Answer

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

Question 3

Which of the following best describes the difference between constructive and destructive interference in the double-slit experiment?

Accepted Answer

Constructive interference occurs when the peaks of two waves coincide, resulting in bright regions; destructive interference occurs when a peak and a trough coincide, resulting in dark regions.

Question 4

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

Accepted Answer

$$E = h
u$$

Question 5

The Bohr model of the hydrogen atom introduced the concept of quantized energy levels. Which equation gives the energy of the $$nth $$orbit in a hydrogen atom?

Accepted Answer

$$E_n = -\frac{k}{n^2$}$$

Question 6

Which of the following is a correct set of quantum numbers for an electron in a 3p orbital?

Accepted Answer

$$n=3,\ \ell=1,\ m_\ell=0,\ m_s=+\frac{1}{2}$$

Question 7

Which of the following electron configurations represents a transition metal in its ground state?

Accepted Answer

[Ar]$$4s^2$$ $$3d^3$$

Question 8

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

Accepted Answer

Pauli Exclusion Principle

Question 9

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

Accepted Answer

$$	ext{Na}^+$$

Question 10

Which of the following best explains why the first ionization energy generally increases across a period?

Accepted Answer

The effective nuclear charge increases, pulling electrons closer to the nucleus and making them harder to remove.

Question 11

Which of the following elements would you expect to have the most negative electron affinity?

Accepted Answer

Chlorine (Cl)

Question 12

Which of the following is the correct abbreviated electron configuration for calcium ($$	ext{Ca}$$)?

Accepted Answer

[Ar]$$4s^2$$

Question 13

Which of the following best describes Hund’s Rule?

Accepted Answer

Electrons fill degenerate orbitals singly with parallel spins before pairing.

Question 14

Which of the following transitions in a hydrogen atom would emit a photon with the highest energy?

Accepted Answer

$$n=2 to$$ $$n=1$$

Question 15

Which of the following statements about the photoelectric effect is correct?

Accepted Answer

Electrons are ejected only if the light has a frequency above a certain threshold, regardless of intensity.

Question 16

Which of the following best describes the Heisenberg Uncertainty Principle?

Accepted Answer

It is impossible to simultaneously know both the exact position and exact momentum of a particle.

Question 17

Which of the following ions is larger in size than its parent atom?

Accepted Answer

$$	ext{Cl}^-$$

Question 18

Which of the following best explains why the 4s orbital is filled before the 3d orbital in the ground-state electron configuration of potassium?

Accepted Answer

The 4s orbital is lower in energy than the 3d orbital for potassium.

Question 19

Which of the following is the correct electron configuration for the Fe$$^{2+}$$ ion?

Accepted Answer

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

Electronic Structure and Periodic Properties of Elements

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