$$\Delta E = -2.18 \times 10$$^{-18}$$ \ \mathrm{J} \left( \frac{1}{n_f^2$} - \frac{1}{n_i^2$} \right)$$

Question 1

According to the Bohr model, which statement best describes the allowed locations for electrons in a hydrogen atom?

Accepted Answer

Electrons can only exist in specific orbits with quantized energies.

Question 2

Which equation correctly expresses the energy change when an electron transitions between two energy levels in a hydrogen atom?

Accepted Answer

$$\Delta E = -2.18 	imes 10$$^{-18}$$ \ \mathrm{J} \left( \frac{1}{n_f^2$} - \frac{1}{n_i^2$} ight)$$

Question 3

A hydrogen atom emits a photon as its electron falls from $$n=4 to$$ $$n=2. $$What is the sign of $$\Delta E$$ and what does it represent?

Accepted Answer

$$\Delta E is $$negative; energy is emitted.

Question 4

Which of the following best explains why the Bohr model fails for atoms with more than one electron?

Accepted Answer

It cannot account for electron-electron repulsions and does not explain quantization for multi-electron systems.

Question 5

According to de Broglie, what is the wavelength $$\lambda of a $$particle with mass $$m$$ and velocity $$u$$?

Accepted Answer

$$\lambda = \frac{h}{m u}$$

Question 6

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number $$l$$

Question 7

How many $$d$$ orbitals are present in the $$n=3$$ shell?

Accepted Answer

5

Question 8

Which of the following statements about the Heisenberg uncertainty principle is correct?

Accepted Answer

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

Question 9

What is the maximum number of orbitals in the $$n=2$$ shell?

Accepted Answer

4

Question 10

Which orbital type is spherical in shape?

Accepted Answer

$$s$$ orbital

Question 11

A photon with a wavelength of $$1280\ \mathrm{nm} is $$emitted by a hydrogen atom. Which transition does this correspond to?

Accepted Answer

From $$n=5 to$$ $$n=3$$

Question 12

Which quantum number describes the orientation of an orbital in space?

Accepted Answer

Magnetic quantum number $$m_l$$

Question 13

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

Accepted Answer

It does not explain why electron energies are quantized.

Question 14

What is the total number of orbitals in the $$n=4$$ shell?

Accepted Answer

16

Question 15

Which of the following transitions in a hydrogen atom would result in the emission of the highest energy photon?

Accepted Answer

From $$n=4 to$$ $$n=1$$

Question 16

Which quantum number(s) must be the same for two electrons to occupy the same orbital?

Accepted Answer

n, l, and m_l

Question 17

Which of the following best describes the probability of finding an electron in a given region of space according to quantum mechanics?

Accepted Answer

It is proportional to $$\$$psi^2$$ at that point.

Question 18

Which of the following sets of quantum numbers is not allowed for an electron in an atom?

Accepted Answer

$$n=2,\ l=2,\ m_l=0$$

Question 19

Which of the following statements about $$p$$ orbitals is correct?

Accepted Answer

They have two lobes and one angular node.

Question 20

A scientist wants to calculate the wavelength of an electron moving at a certain velocity. Which equation should they use?

Accepted Answer

$$\lambda = \frac{h}{m u}$$

Electronic Structure of Atoms (Part 2): The Bohr Model, Quantum Mechanics, and Atomic Orbitals

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