Question 1

Which of the following best describes a compound?

Accepted Answer

A pure substance made of multiple types of atoms chemically bonded together.

Question 2

An atom of potassium-41 has an atomic number of 19. How many neutrons does it have?

Accepted Answer

$$41 - 19 = 22$$ neutrons

Question 3

Which element is most likely to form a cation with a $$+2$$ charge?

Accepted Answer

Calcium ($$\mathrm{Ca})$$

Question 4

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 5

Which element has the highest electronegativity?

Accepted Answer

Fluorine ($$\mathrm{F})$$

Question 6

A neutral atom of sulfur ($$\mathrm{S}) $$has an atomic number of 16. How many valence electrons does it have?

Accepted Answer

6

Question 7

Which of the following molecules is nonpolar?

Accepted Answer

Carbon dioxide ($$\mathrm{CO_2$})$$

Question 8

What is the geometry of methane ($$\mathrm{CH_4$}) $$according to VSEPR theory?

Accepted Answer

Tetrahedral

Question 9

Which of the following best explains why sodium chloride ($$\mathrm{NaCl}) $$dissolves easily in water?

Accepted Answer

The ionic bonds in $$\mathrm{NaCl}$$ are broken by the strong ion-dipole interactions with water molecules.

Question 10

Which of the following is a correct Lewis structure for the carbonate ion ($$\mathrm{CO_3$^{2-}}$$)?

Accepted Answer

C in the center, one double bond to O, two single bonds to O with negative charges, and resonance among the O atoms.

Question 11

Which of the following intermolecular forces is the strongest?

Accepted Answer

Ionic interactions

Question 12

Which process is endothermic?

Accepted Answer

Melting

Question 13

A solution is made by dissolving glucose in water. Which of the following best describes this solution?

Accepted Answer

Glucose is a nonelectrolyte and does not produce ions in solution.

Question 14

Which of the following best explains why water has a high boiling point compared to other group 16 hydrides?

Accepted Answer

Water molecules form strong hydrogen bonds with each other.

Question 15

Which of the following pairs of atoms would form the most polar covalent bond?

Accepted Answer

Oxygen and hydrogen ($$\mathrm{O-H})$$

Question 16

Which of the following best describes the effect of placing red blood cells in a hypertonic solution?

Accepted Answer

Water leaves the cells, causing them to shrink.

Question 17

Which of the following is a correct statement about the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to achieve eight valence electrons.

Question 18

Which of the following best explains why noble gases are generally unreactive?

Accepted Answer

They have a full valence shell of electrons.

Question 19

Which of the following compounds would have the highest osmolarity per mole of compound dissolved in water?

Accepted Answer

Aluminum sulfate ($$\mathrm{Al_2$(SO_4$)_3})$$

Question 20

Which of the following best describes the geometry of ammonia ($$\mathrm{NH_3$}$$)?

Accepted Answer

Trigonal pyramidal

GOB Chemistry Study Guide: Building Blocks of Molecules & Molecular Structure

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