Question 1

What is an atom?

Accepted Answer

The smallest particle of ordinary matter that forms a chemical element

(everything is composed of atoms)

Question 2

What are the three main subatomic particles?

Accepted Answer

Protons, neutrons, and electrons

(almost every atom contains these three subatomic particles)

Question 3

What are protons?

Accepted Answer

A type of subatomic particle that is positively charged and located in the atomic nucleus

Question 4

What are neutrons?

Accepted Answer

A type of subatomic particle that has no charge and is located in the atomic nucleus

Question 5

What are electrons?

Accepted Answer

A type of subatomic particle that is negatively charged and is located in the electron cloud

Question 6

What is the atomic nucleus?

Accepted Answer

A dense region in the center of atoms that contains neutrons and protons

Question 7

What is the electron cloud?

Accepted Answer

All the electrons that "orbit" the nucleus of an atom

Question 8

What is an atomic mass unit (amu)?

Accepted Answer

A unit used to measure the weights of single atoms

(since atoms are incredibly small, this unit is also incredibly small; a single atom of nitrogen weighs 14amu)

Question 9

What is an element?

Accepted Answer

A pure substance made entirely of atoms with the same atomic number

Cannot be broken into simpler substances by a chemical reaction

Question 10

What is an atom's mass number?

Accepted Answer

The total number of protons and neutrons in the atomic nucleus

(approximately equal to the atomic mass; oxygen has 8 protons and 8 neutrons, for a mass number of 16)

Question 11

What is atomic mass?

Accepted Answer

The mass of a single atom, expressed in atomic mass units

(approximately equal to the mass number)

Question 12

What is atomic number?

Accepted Answer

The number of protons in an atom

Determines the atom's properties, and which element it is

Atoms, AP Chemistry Flashcards