$$\text{Atomic mass} = \text{Number of protons} + \text{Number of neutrons}$$

Question 1

Which statement best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 2

Which of the following elements is NOT a major biological element found in the human body?

Accepted Answer

Fluorine (F)

Question 3

A neutral atom of sodium (Na) has an atomic number of 11. How many electrons does it have?

Accepted Answer

$$11$$

Question 4

Which of the following best explains why noble gases are chemically stable?

Accepted Answer

They have a full valence shell of electrons.

Question 5

Which of the following ions is polyatomic and carries a negative charge?

Accepted Answer

SO$$_4$$^{2-}$$ (sulfate)

Question 6

Which process is exothermic?

Accepted Answer

Condensation

Question 7

What is the total number of electrons in a neutral oxygen atom?

Accepted Answer

$$8$$

Question 8

Which of the following best describes a covalent bond?

Accepted Answer

Sharing of electrons between two nonmetals.

Question 9

Which molecule would you expect to have hydrogen bonding?

Accepted Answer

NH$$_3$$

Question 10

Which of the following best explains why water (H$$_2O) is a $$polar molecule?

Accepted Answer

It has a bent geometry and a difference in electronegativity between H and O.

Question 11

Which of the following statements about the periodic table is TRUE?

Accepted Answer

Groups are vertical columns indicating similar chemical properties.

Question 12

A solution is prepared by dissolving NaCl in water. Which term best describes NaCl in this context?

Accepted Answer

Electrolyte

Question 13

Which of the following best describes the role of valence electrons in chemical bonding?

Accepted Answer

They are involved in chemical bonding and determine reactivity.

Question 14

Which of the following ions is isoelectronic with neon (Ne)?

Accepted Answer

F$$^-$$

Question 15

Which of the following molecules is nonpolar?

Accepted Answer

CO$$_2$$

Question 16

Which statement about hydrogen bonds is CORRECT?

Accepted Answer

They require a lone pair on O, N, or F.

Question 17

Which of the following best describes the trend in ionization energy across a period in the periodic table?

Accepted Answer

Ionization energy increases from left to right.

Question 18

A sample contains 80% water and 20% salt by mass. What is the percent composition of salt?

Accepted Answer

$$20\%$$

Question 19

Which of the following is the correct formula for calculating atomic mass?

Accepted Answer

$$	ext{Atomic mass} = 	ext{Number of protons} + 	ext{Number of neutrons}$$

Question 20

Which of the following best describes a cation?

Accepted Answer

An ion with a positive charge formed by losing electrons.

GOB Chemistry Study Guide: Building Blocks of Molecules, Atomic Structure, Periodic Table, Bonding, and Solution Chemistry

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