Question 1

Which of the following statements best explains why isotopes of the same element have nearly identical chemical properties?

Accepted Answer

Isotopes have the same number of protons and electrons, so their electron configurations and chemical behavior are the same.

Question 2

A neutral atom of phosphorus (Z = 15) has which of the following electron configurations in its ground state?

Accepted Answer

1s2 2s2 2p6 3s2 3p3

Question 3

Which of the following ions has the same number of electrons as a neutral neon atom?

Accepted Answer

Na+

Question 4

Which element is the most electronegative?

Accepted Answer

Fluorine

Question 5

A molecule of carbon dioxide (CO2) is nonpolar even though it contains polar bonds. Which statement best explains this observation?

Accepted Answer

The molecule is linear and symmetrical, so the bond dipoles cancel each other out.

Question 6

Which of the following best describes the hybridization and geometry of the central atom in ammonia (NH3)?

Accepted Answer

sp3 hybridization, tetrahedral electron geometry

Question 7

Which of the following molecules is expected to be polar?

Accepted Answer

NF3

Question 8

A student draws a Lewis structure for the nitrate ion (NO3-) with one double bond between N and O, and two single bonds to the other oxygens. What is the significance of drawing all possible resonance structures for this ion?

Accepted Answer

The actual structure is a resonance hybrid, with the double bond character delocalized over all three oxygens.

Question 9

Which of the following best describes the Pauli Exclusion Principle?

Accepted Answer

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

Question 10

Given the following Lewis structure for formaldehyde (CH2O), what is the formal charge on the oxygen atom? (O has 6 valence electrons, 4 nonbonding electrons, and is involved in 2 bonds)

Accepted Answer

0

Question 11

Which of the following molecules contains a functional group classified as a carbonyl?

Accepted Answer

Acetone (CH3COCH3)

Question 12

Which of the following best describes the difference between a cation and an anion?

Accepted Answer

A cation has lost electrons and is positively charged, while an anion has gained electrons and is negatively charged.

Question 13

Which of the following molecules is a hydrocarbon?

Accepted Answer

Propane (C3H8)

Question 14

A molecule has three electron groups around the central atom and no lone pairs. What is its electron geometry and hybridization?

Accepted Answer

Trigonal planar, sp2

Question 15

Which of the following best explains why the octet rule is not always obeyed in molecules containing elements from period 3 or higher?

Accepted Answer

Elements in period 3 or higher have d orbitals available, allowing them to expand their valence shell beyond eight electrons.

Question 16

Which of the following best describes the process for drawing a Lewis structure for a molecule?

Accepted Answer

Count total valence electrons, connect atoms with single bonds, complete octets, form multiple bonds if needed, and check formal charges.

Question 17

Which of the following is a correct condensed electron configuration for chlorine (Z = 17)?

Accepted Answer

[Ne] 3s2 3p5

Question 18

Which of the following best describes a resonance hybrid?

Accepted Answer

A weighted average of all valid resonance structures, representing the true electron distribution.

Question 19

Which of the following molecules would be expected to have a nonzero dipole moment (i.e., be polar)?

Accepted Answer

SO2

Question 20

A student is asked to identify the functional groups in the molecule CH3CH2COOH. Which groups are present?

Accepted Answer

Carboxylic acid and alkane

General Chemistry Study Guide: Atomic Structure, Bonding, and Molecular Properties

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