Question 1

Which of the following best describes a molecule?

Accepted Answer

A group of atoms bonded together, representing the smallest fundamental unit of a chemical compound

Question 2

What is the atomic number of an atom with 3 protons, 4 neutrons, and 3 electrons?

Accepted Answer

$$3$$

Question 3

Which of the following statements about covalent bonds is correct?

Accepted Answer

They are formed when atoms share pairs of electrons

Question 4

A molecule of water ($$\mathrm{H_2O}) is $$considered polar because:

Accepted Answer

There is an unequal sharing of electrons, resulting in partial charges on the atoms

Question 5

Which of the following best explains why atoms form chemical bonds?

Accepted Answer

To attain a stable electron configuration

Question 6

If an atom has an atomic mass of $$9$$ and an atomic number of $$4$$, how many neutrons does it have?

Accepted Answer

$$5$$

Question 7

Which of the following is true about non-polar covalent bonds?

Accepted Answer

Electrons are shared equally between atoms

Question 8

Electronegativity is best defined as:

Accepted Answer

The ability of an atom to attract shared electrons in a chemical bond

Question 9

Which of the following scenarios would most likely result in a polar covalent bond?

Accepted Answer

An atom with much higher electronegativity shares electrons with an atom of much lower electronegativity

Question 10

A student claims that in a molecule of $$\mathrm{O_2$}$$, the electrons are shared unequally, making it a polar molecule. Is this correct? Why or why not?

Accepted Answer

No, because both atoms have the same electronegativity, so electrons are shared equally

Question 11

Which of the following best describes the difference between an element and a compound?

Accepted Answer

An element is a pure substance made of only one kind of atom, while a compound is made of two or more different elements chemically bonded

Question 12

Which of the following is a real-world example of a polar covalent bond?

Accepted Answer

The bond between hydrogen and oxygen in a water molecule

Question 13

If a molecule has a region with a partial positive charge and another with a partial negative charge, what type of molecule is it?

Accepted Answer

Polar molecule

Question 14

Which of the following best explains why water is an excellent solvent for ionic compounds?

Accepted Answer

Water molecules are polar and can interact with both positive and negative ions

Question 15

A scientist observes that a molecule has equal sharing of electrons between its atoms. Which of the following is most likely true about this molecule?

Accepted Answer

It is a non-polar molecule

Question 16

Which of the following best describes what happens when two atoms with very different electronegativities form a bond?

Accepted Answer

They form an ionic bond

Question 17

Which of the following is the correct formula to calculate the number of neutrons in an atom?

Accepted Answer

$$	ext{Number of neutrons} = 	ext{Atomic mass} - 	ext{Atomic number}$$

Question 18

Which of the following best describes a compound?

Accepted Answer

A substance made of two or more elements chemically bonded in fixed proportions

Question 19

A patient is given a medication that contains a molecule with polar covalent bonds. Which property of this molecule is most likely to affect how it interacts with water in the body?

Accepted Answer

It will be hydrophilic and dissolve well in water

Question 20

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

Accepted Answer

Water is polar and stabilizes the positive and negative ions formed from $$\mathrm{NaCl}$$

Atoms, Molecules, and Chemical Bonds: Foundations for General Biology

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