Question 1

Which of the following statements best describes an element?

Accepted Answer

A substance that cannot be broken down into other substances by chemical reactions.

Question 2

Which of the following is a compound?

Accepted Answer

$$\mathrm{H}_2\mathrm{O}$$

Question 3

A sodium atom has 11 protons and 11 electrons. What happens to its charge if it loses one electron?

Accepted Answer

It becomes positively charged.

Question 4

Which type of chemical bond involves the sharing of electron pairs between atoms?

Accepted Answer

Covalent bond

Question 5

Why are noble gases such as neon (Ne) generally unreactive?

Accepted Answer

They have a full valence shell of electrons.

Question 6

Which of the following best explains why water ($$\mathrm{H}_2\mathrm{O}) is a $$polar molecule?

Accepted Answer

Oxygen is more electronegative than hydrogen, creating partial charges.

Question 7

Which of the following is true about isotopes?

Accepted Answer

They have different numbers of neutrons.

Question 8

A patient is diagnosed with a goiter due to iodine deficiency. Which dietary change would most directly address this condition?

Accepted Answer

Switch to iodized salt.

Question 9

Which of the following best describes a hydrogen bond?

Accepted Answer

A weak attraction between a hydrogen atom and an electronegative atom.

Question 10

Which element is the most abundant in the human body by mass?

Accepted Answer

Oxygen

Question 11

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

Accepted Answer

Water molecules surround and separate the ions due to their polarity.

Question 12

Which of the following is the strongest type of chemical bond?

Accepted Answer

Covalent bond

Question 13

A carbon atom has an atomic number of 6 and a mass number of 14. How many neutrons does it have?

Accepted Answer

$$14 - 6 = 8$$ neutrons

Question 14

Which of the following best describes van der Waals interactions?

Accepted Answer

Weak attractions due to temporary partial charges in all atoms and molecules.

Question 15

Which of the following pairs of elements are most likely to form an ionic bond?

Accepted Answer

Na and Cl

Question 16

Which property of water is primarily responsible for its ability to dissolve many ionic compounds?

Accepted Answer

Its polarity

Question 17

Which of the following best explains why morphine can mimic the effects of endorphins in the brain?

Accepted Answer

Morphine has a similar molecular shape to endorphins, allowing it to bind to the same receptors.

Question 18

Which of the following is true about chemical reactions?

Accepted Answer

They involve the making and breaking of chemical bonds.

Question 19

How many valence electrons does a calcium (Ca) atom have?

Accepted Answer

2

Question 20

Which element is more electronegative: chlorine or aluminum (Al)?

Accepted Answer

Chlorine

Bio chapter 2

Study Guide - Practice Questions