Question 1

Which of the following statements best describes the relationship between matter, chemical elements, and atoms?

Accepted Answer

Matter is made up of atoms, which are the smallest units of chemical elements.

Question 2

A carbon atom has 6 protons, 6 neutrons, and 6 electrons. What is its atomic number and mass number?

Accepted Answer

Atomic number = $$6$$, Mass number = $$12$$

Question 3

Which subatomic particle is responsible for the chemical identity of an element?

Accepted Answer

Proton

Question 4

If an oxygen atom has an atomic number of $$8$$ and a mass number of $$16$$, how many neutrons does it have?

Accepted Answer

$$8$$

Question 5

Which of the following atoms is most likely to be chemically unreactive?

Accepted Answer

An atom with a full valence shell

Question 6

According to the octet rule, how many electrons does a nitrogen atom (atomic number $$7) $$have in its valence shell?

Accepted Answer

$$5$$

Question 7

Which of the following best explains why neon (Ne) is chemically unreactive?

Accepted Answer

Its valence shell is full of electrons.

Question 8

How many electrons does an oxygen atom need to fulfill the octet rule?

Accepted Answer

$$2$$

Question 9

Isotopes of an element differ in which of the following?

Accepted Answer

Number of neutrons

Question 10

Carbon-13 and Carbon-14 are isotopes of carbon. What is the main difference between them?

Accepted Answer

Carbon-14 has more neutrons than Carbon-13.

Question 11

A radioactive isotope has a half-life of $$5730$$ years. How many years will it take for a sample to decay to $$\frac{1}{4} of $$its original amount?

Accepted Answer

$$11460$$ years

Question 12

Which of the following is NOT a use of radioactive isotopes in biology and medicine?

Accepted Answer

Increasing the number of electrons in atoms

Question 13

Which of the following best describes a covalent bond?

Accepted Answer

An interaction resulting from the sharing of electrons between two atoms

Question 14

What makes a covalent bond nonpolar?

Accepted Answer

The bonded atoms share electrons equally and have similar electronegativities.

Question 15

Which of the following is true about polar covalent bonds?

Accepted Answer

One atom has a partial negative charge.

Question 16

Which type of bond holds the hydrogens and oxygen together within a water molecule?

Accepted Answer

Covalent bond

Question 17

Which of the following is a very weak non-covalent chemical bond commonly found in biology?

Accepted Answer

Van der Waals bond

Question 18

What is the main difference between an anion and a cation?

Accepted Answer

Anions have gained electrons, cations have lost electrons.

Question 19

Which of the following best describes an ionic bond?

Accepted Answer

Atoms of opposite charges attract each other.

Chemistry Foundations for Microbiology: Atoms, Elements, and Chemical Bonds

Study Guide - Practice Questions