Question 1

Which of the following elements is NOT one of the six most abundant elements in living organisms, commonly referred to as CHNOPS?

Accepted Answer

Calcium

Question 2

An atom of oxygen has an atomic number of 8 and a mass number of 16. How many neutrons does it have?

Accepted Answer

$$8$$

Question 3

Which statement best explains why isotopes of the same element behave similarly in chemical reactions?

Accepted Answer

They have the same number of protons and electrons.

Question 4

A radioactive isotope has a half-life of $$5,730$$ years. How many years must pass for a sample to decay to $$\frac{1}{4} of $$its original amount?

Accepted Answer

$$11,460$$

Question 5

Which of the following is TRUE about valence electrons?

Accepted Answer

They determine the chemical reactivity of an atom.

Question 6

According to the octet rule, how many electrons does an oxygen atom need to gain to fill its valence shell?

Accepted Answer

$$2$$

Question 7

Which of the following best describes a cation?

Accepted Answer

An atom that has lost electrons and has a positive charge.

Question 8

If a carbon atom has 6 protons, 7 neutrons, and 6 electrons, what is its mass number?

Accepted Answer

$$13$$

Question 9

Which of the following is a correct statement about the periodic table?

Accepted Answer

It arranges elements by increasing atomic number.

Question 10

A nitrogen atom has an atomic number of 7. How many electrons are in a neutral nitrogen atom?

Accepted Answer

$$7$$

Question 11

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

Accepted Answer

Increasing the number of valence electrons in atoms

Question 12

Which of the following statements about electron shells is TRUE?

Accepted Answer

Electrons in shells farther from the nucleus are higher in energy.

Question 13

How are carbon-13 and nitrogen-15 isotopes different from the more abundant carbon-12 and nitrogen-14?

Accepted Answer

Each has one extra neutron.

Question 14

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 15

If the atomic number of an element is equal to the number of protons, which equation correctly represents the relationship between atomic number ($$Z$$), number of protons ($$p$$), and number of neutrons ($$n$$)?

Accepted Answer

$$Z = p$$

Question 16

Which of the following is TRUE about the mass number of an atom?

Accepted Answer

It is the sum of protons and neutrons.

Question 17

Which of the following is a trace element required in small amounts for life?

Accepted Answer

Iron

Question 18

Which of the following is the chemical formula for glucose?

Accepted Answer

$$C_6H_{12}O_6$

Question 19

Which of the following is the correct definition of a chemical element?

Accepted Answer

A pure substance made of only one type of atom.

Question 20

Which of the following statements about atoms is correct?

Accepted Answer

Atoms are made of protons, neutrons, and electrons.

General Biology Study Notes: Chemistry of Life and Atomic Structure

Study Guide - Practice Questions

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