A photon is emitted and its energy is given by $$E = -2.18 \times 10$$^{-18}$$ \left( \frac{1}{2^2$} - \frac{1}{4^2$} \right)\ \text{J}$$

Question 1

Which of the following best describes the Aufbau Principle?

Accepted Answer

Electrons fill the lowest energy orbitals first before moving to higher energy orbitals.

Question 2

According to the Pauli Exclusion Principle, which of the following is true for electrons in the same orbital?

Accepted Answer

They must have opposite spins.

Question 3

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Azimuthal quantum number ($$l)$$

Question 4

What is the maximum number of electrons that can occupy the $$n=3$$ shell?

Accepted Answer

$$18$$

Question 5

Which set of quantum numbers 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 of the following electron configurations violates Hund's Rule?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^3$$ with all three $$2p$$ electrons paired in one orbital

Question 7

Which orbital is described by the quantum numbers $$n=3$$, $$l=2$$, $$m_l=0$$?

Accepted Answer

$$3d_{z^2$}$$

Question 8

How many nodes are present in a $$2p$$ orbital?

Accepted Answer

$$1$$

Question 9

Which of the following statements about the energy of orbitals in a multi-electron atom is correct?

Accepted Answer

$$4s is $$filled before $$3d$$ because $$4s$$ has lower energy than $$3d.$$

Question 10

Which of the following best explains why the $$2s$$ orbital is lower in energy than the $$2p$$ orbital in a multi-electron atom?

Accepted Answer

$$2s$$ electrons penetrate closer to the nucleus, experiencing less shielding.

Question 11

Which of the following is the correct electron configuration for a neutral oxygen atom?

Accepted Answer

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

Question 12

Which quantum number(s) determine the orientation of an orbital in space?

Accepted Answer

Magnetic quantum number ($$m_l)$$

Question 13

A hydrogen atom makes a transition from $$n=4 to$$ $$n=2. $$Which of the following is true?

Accepted Answer

A photon is emitted and its energy is given by $$E = -2.18 	imes 10$$^{-18}$$ \left( \frac{1}{2^2$} - \frac{1}{4^2$} ight)\ 	ext{J}$$

Question 14

Which of the following sets of quantum numbers describes a $$4p$$ electron?

Accepted Answer

$$n=4,\ l=1,\ m_l=0,\ m_s=+\frac{1}{2}$$

Question 15

Which of the following is a valid set of quantum numbers for an electron in a $$3d$$ orbital?

Accepted Answer

$$n=3,\ l=2,\ m_l=2,\ m_s=-\frac{1}{2}$$

Question 16

Which of the following best describes the meaning of a node in an atomic orbital?

Accepted Answer

A region where the probability of finding an electron is zero.

Question 17

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

Accepted Answer

$$n=3 to$$ $$n=1$$

Question 18

Which of the following is the correct order of filling for the following orbitals according to the Aufbau Principle?

Accepted Answer

$$1s \rightarrow 2s \rightarrow 2p \rightarrow 3s \rightarrow 3p \rightarrow 4s \rightarrow 3d$$

Question 19

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

Accepted Answer

There are five $$d$$ orbitals in each energy level where $$l=2 is $$allowed.

General Chemistry Study Guide: Electron Configurations, Aufbau Principle, and Quantum Numbers

Study Guide - Practice Questions