Question 1

Which of the following best describes the Pauli Exclusion Principle as it applies to electron configuration in atoms?

Accepted Answer

No two electrons in an atom can have the same set of four quantum numbers.

Question 2

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

The azimuthal (angular momentum) quantum number $$l$$

Question 3

Which element has the highest first ionization energy among the following?

Accepted Answer

Neon ($$\mathrm{Ne})$$

Question 4

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

Accepted Answer

$$Z_{\mathrm{eff}}$$ increases across a period from left to right.

Question 5

Which of the following ions is isoelectronic with argon ($$\mathrm{Ar}$$)?

Accepted Answer

$$\mathrm{Ca$$^{2+}$$}$$

Question 6

A sample of magnesium reacts with hydrochloric acid to produce hydrogen gas. Which equation correctly represents this reaction?

Accepted Answer

$$\mathrm{Mg(s) + 2HCl(aq) \rightarrow $$MgCl_2$$(aq) + H_2$(g)}$$

Question 7

Which of the following best explains why fluorine is more electronegative than chlorine?

Accepted Answer

Fluorine has a smaller atomic radius and a higher effective nuclear charge.

Question 8

Which of the following molecules is nonpolar, despite having polar bonds?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 9

Which of the following best describes the hybridization of the central atom in methane ($$\mathrm{CH_4$}$$)?

Accepted Answer

$$sp^3$$

Question 10

Which of the following statements about resonance structures is correct?

Accepted Answer

Resonance structures represent delocalized electrons within a molecule.

Question 11

Which of the following best explains why the bond angle in water ($$\mathrm{H_2O}) is $$less than the ideal tetrahedral angle?

Accepted Answer

Lone pairs on oxygen repel the bonding pairs more strongly, reducing the bond angle.

Question 12

Which of the following molecules contains a triple bond?

Accepted Answer

$$\mathrm{N_2$}$$

Question 13

Which of the following is the correct electron configuration for the ground state of $$\mathrm{Fe$$^{2+}$$}$$?

Accepted Answer

$$[\mathrm{Ar}]\ 3d^6$

Question 14

Which of the following best describes a sigma ($$\sigma) $$bond?

Accepted Answer

A bond formed by the head-on overlap of two atomic orbitals.

Question 15

Which of the following statements about ionic compounds is correct?

Accepted Answer

They generally have high melting points due to strong electrostatic forces.

Question 16

A molecule has the formula $$\mathrm{AX_2E_2} ($$where E represents a lone pair). What is its molecular geometry according to VSEPR theory?

Accepted Answer

Bent

Question 17

Which of the following best explains why sodium chloride ($$\mathrm{NaCl}) $$conducts electricity when dissolved in water but not as a solid?

Accepted Answer

Ions are free to move in solution, allowing electrical conductivity.

Question 18

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

Accepted Answer

Atomic radius decreases due to increasing effective nuclear charge.

Question 19

Which of the following is the best explanation for the high melting point of magnesium oxide ($$\mathrm{MgO}$$)?

Accepted Answer

It has strong ionic bonds between $$\mathrm{Mg$$^{2+}$$}$$ and $$\mathrm{O$$^{2-}$$}$$ ions.

Question 20

Which of the following best describes the concept of lattice energy in ionic compounds?

Accepted Answer

The energy required to separate one mole of an ionic solid into its gaseous ions.

General Chemistry Exam 3 Review: Atomic Structure, Periodic Properties, Chemical Bonding, and Molecular Geometry

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