$$E = \frac{6.626 \times 10$$^{-34}$$ \times 3.00 \times 10^8$}{500 \times 10$$^{-9}$$} = 3.98 \times 10$$^{-19}$$ J

Question 1

Which of the following statements best explains why fireworks display different colors when ignited?

Accepted Answer

Each element emits a unique pattern of wavelengths of light when its atoms are excited, producing characteristic colors.

Question 2

A sodium atom is excited in a flame test. Which electron transition is responsible for the emission of visible light?

Accepted Answer

An electron moves from a higher to a lower energy level, releasing energy as a photon.

Question 3

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

Accepted Answer

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

Question 4

A neutron (mass $$1.66 	imes 10$$^{-27}$$ kg) is moving at 2200$ m/s. What is its de Broglie wavelength?

Accepted Answer

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

Question 5

Which of the following quantum number sets is NOT allowed for an electron in an atom?

Accepted Answer

$$n=2,\ l=2,\ m_l=0,\ m_s=+\frac{1}{2}$$

Question 6

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 7

What is the condensed electron configuration for vanadium (V, atomic number 23)?

Accepted Answer

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

Question 8

Which of the following best describes the shape and number of nodes for a 3s orbital?

Accepted Answer

Spherical shape with 2 nodes

Question 9

Which equation is used to calculate the wavelengths of light emitted by hydrogen according to the Rydberg formula?

Accepted Answer

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

Question 10

Which of the following is a real-world application of the photoelectric effect?

Accepted Answer

Photomultiplier tubes in scientific instruments

Question 11

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number $$l$$

Question 12

Why do the 4s orbitals fill before the 3d orbitals in the periodic table?

Accepted Answer

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

Question 13

A photon has a wavelength of $$500 nm. $$What is its energy in Joules? ($$h = 6.626 	imes 10$$^{-34}$$ J·s, c = 3.00$$ 	imes $$10^8 m/s)$$

Accepted Answer

$$E = \frac{6.626 	imes 10$$^{-34}$$ 	imes 3.00 	imes 10^8$}{500 	imes 10$$^{-9}$$} = 3.98 	imes 10$$^{-19}$$ J

Question 14

Which of the following best describes Hund's Rule?

Accepted Answer

Electrons fill degenerate orbitals singly with parallel spins before pairing.

Question 15

Which of the following is the correct full electron configuration for oxygen (O, atomic number 8)?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^4$$

Question 16

Which of the following best explains why X-rays have higher resolution than visible light in imaging applications?

Accepted Answer

X-rays have much shorter wavelengths than visible light, allowing them to resolve smaller details.

Question 17

Which of the following is a valid set of quantum numbers for an electron in a 4d orbital?

Accepted Answer

$$n=4,\ l=2,\ m_l=1,\ m_s=+\frac{1}{2}$$

Question 18

Which of the following best describes the difference between core and valence electrons?

Accepted Answer

Core electrons are those in filled inner shells, while valence electrons are in the outermost shell and determine chemical properties.

Electronic Structure of Atoms: Quantum Theory, Atomic Orbitals, and Electron Configurations

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