$$\frac{10}{100} \times 100\% = 10\%$$

$$\text{Number of neutrons} = \text{Mass number} - \text{Atomic number}$$

Question 1

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

Accepted Answer

An element is a pure substance made of only one kind of atom, while an atom is the smallest unit of that element that retains its properties.

Question 2

A neutral atom of sodium (Na) has an atomic number of 11 and a mass number of 23. How many neutrons does it have?

Accepted Answer

$$23 - 11 = 12$$ neutrons

Question 3

Which of the following statements about subatomic particles is correct?

Accepted Answer

Electrons have a negative charge and are found in electron shells around the nucleus.

Question 4

Which of the following best explains why atoms with unfilled valence shells are reactive?

Accepted Answer

They seek to gain, lose, or share electrons to achieve a full valence shell, which increases stability.

Question 5

A radioactive isotope of carbon, carbon-14, has an atomic number of 6 and a mass number of 14. What is the number of neutrons in carbon-14?

Accepted Answer

$$14 - 6 = 8$$ neutrons

Question 6

Which of the following best describes a cation?

Accepted Answer

An atom that has lost an electron and is positively charged.

Question 7

Which of the following is true regarding the energy of electrons in different shells?

Accepted Answer

Electrons in shells further from the nucleus have more stored electrical energy.

Question 8

Which of the following is a correct representation of a water molecule using chemical notation?

Accepted Answer

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

Question 9

A solution contains 10 grams of glucose dissolved in 100 mL of water. What is the percent concentration of glucose in this solution?

Accepted Answer

$$\frac{10}{100} 	imes 100\% = 10\%$$

Question 10

Which of the following best describes a molecule?

Accepted Answer

Two or more atoms chemically bonded together.

Question 11

Which of the following is an example of a compound?

Accepted Answer

$$\mathrm{H}_2\mathrm{O} ($$water)

Question 12

If an atom has 17 protons, 18 neutrons, and 17 electrons, what is its mass number?

Accepted Answer

$$17 + 18 = 35$$

Question 13

Which of the following best explains why radioisotopes are useful in medical imaging?

Accepted Answer

They emit electromagnetic energy during decay, which can be detected and used to trace biological molecules.

Question 14

Which of the following is the correct formula for calculating the number of neutrons in an atom?

Accepted Answer

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

Question 15

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

Accepted Answer

A molecule is two or more atoms bonded together, while a compound is a molecule made of different elements.

Question 16

Which of the following is true about the valence shell of an atom?

Accepted Answer

It is the outermost shell and determines the chemical properties of the atom.

Question 17

A patient is injected with a radioisotope for a nuclear cardiac stress test. What property of the radioisotope allows it to be traced in the body?

Accepted Answer

It emits electromagnetic energy as it decays, which can be detected by imaging equipment.

Question 18

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

Accepted Answer

Matter is made of elements, which are made of atoms.

Question 19

Which of the following is a correct statement about ions?

Accepted Answer

An anion is an atom that has gained an electron and is negatively charged.

Question 20

Which of the following best explains why compounds have properties different from the atoms that make them up?

Accepted Answer

Chemical bonding changes the arrangement and interactions of electrons, resulting in new properties.

Chemical Level of Organization: Foundations for Anatomy & Physiology

Study Guide - Practice Questions