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

Question 1

Which of the following best describes a compound?

Accepted Answer

A substance consisting of two or more different elements chemically bonded in fixed proportions.

Question 2

Which subatomic particle determines the atomic number of an element?

Accepted Answer

Proton

Question 3

If a sodium atom ($$\mathrm{Na}) $$has an atomic number of 11 and an atomic mass of 23, how many neutrons does it have?

Accepted Answer

$$23 - 11 = 12$$

Question 4

Which of the following is NOT one of the 'big 4' elements of life?

Accepted Answer

Sodium

Question 5

What happens to an atom if the number of electrons changes but the number of protons remains the same?

Accepted Answer

It becomes an ion.

Question 6

Which type of bond involves the sharing of electron pairs between atoms with similar electronegativities?

Accepted Answer

Nonpolar covalent bond

Question 7

A hydrogen bond is best described as:

Accepted Answer

A weak attraction between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.

Question 8

Which of the following statements about valence electrons is correct?

Accepted Answer

Valence electrons determine the chemical reactivity of an atom.

Question 9

If a carbon atom has 6 protons, 6 neutrons, and 6 electrons, what is its atomic mass?

Accepted Answer

$$12$$

Question 10

Which of the following best explains why water molecules are polar?

Accepted Answer

Oxygen is more electronegative than hydrogen, causing an unequal sharing of electrons.

Question 11

What is the charge of a fluorine ion ($$\mathrm{F}^-) $$that has gained one electron?

Accepted Answer

$$-1$$

Question 12

Which of the following is true about isotopes?

Accepted Answer

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

Question 13

Which of the following bonds is the weakest?

Accepted Answer

Van der Waals interaction

Question 14

If an atom has 8 electrons, how many electrons are in its valence shell?

Accepted Answer

8

Question 15

Which of the following best describes an ionic bond?

Accepted Answer

A bond formed by the transfer of electrons from one atom to another.

Question 16

What information does the group (column) number in the periodic table provide about an element?

Accepted Answer

The number of valence electrons.

Question 17

Which of the following atoms is NOT at its lowest energy state in the molecule below?

$$\mathrm{H}-\mathrm{O}-\mathrm{C}-\mathrm{H}-\mathrm{C}-\mathrm{H}$$

Accepted Answer

Carbon

Question 18

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

Accepted Answer

The bond between hydrogen and oxygen in water.

Question 19

Which equation correctly represents the calculation of atomic mass?

Accepted Answer

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

Question 20

Which of the following best describes electronegativity?

Accepted Answer

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

Atoms, Elements, and Chemical Bonds: Foundations of General Biology

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