Ch. 4

Question 1

Atom

Answer 1

The smallest unit of an element that maintains the properties of that element.

Question 2

Electron

Answer 2

A subatomic particle that has a negative charge.

Question 3

Nucleus

Answer 3

In physical science, an atom’s central region, which is made up of protons and neutrons.

Question 4

Electron Clouds

Answer 4

A region around the nucleus of an atom where electrons are likely to be found.

Question 5

Protons

Answer 5

A subatomic particle that has a positive charge and that is found in the nucleus of an atom.

Question 6

Atomic Mass Unit

Answer 6

A unit of mass that describes the mass of an atom or molecules.

Question 7

Neutrons

Answer 7

A subatomic particle that has no charge and that is found in the nucleus of an atom.

Question 8

Atomic Number

Answer 8

The number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element.

Question 9

Isotope

Answer 9

each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.

Question 10

Mass Number

Answer 10

the total number of protons and neutrons in a nucleus.

Question 11

Atomic Mass

Answer 11

the mass of an atom of a chemical element expressed in atomic mass units. It is approximately equivalent to the number of protons and neutrons in the atom (the mass number) or to the average number allowing for the relative abundances of different isotopes.