Chapter Two Key Terms

Question 1

Atom

Answer 1

the smallest and simplest particle of an element

Question 2

Atomic Theory

Answer 2

A set of assumptions proposed by English scientist John Dalton to explain the chemical behavior of matter.

Question 3

What are the three subatomic particles?

Answer 3

Protons, neutrons, electrons

Question 4

Atomic Number (Z)

Answer 4

number of protons in the nucleus of a given element and the number of electrons

Question 5

Mass number (A)

Answer 5

The total number of protons and neutrons in an atom

Question 6

Isotopes

Answer 6

Atoms with identical atomic numbers but different mass numbers.

Question 7

Atomic Weight

Answer 7

The weighted average mass of an element’s atoms.

Question 8

Shells (electron)

Answer 8

A grouping of electrons in an atom according to energy.

Question 9

Subshells (electron)

Answer 9

A grouping of electrons in a shell according to the shape of the region of space they occupy.

Question 10

Orbitals

Answer 10

A region of space within an atom where an electron in a given subshell can be found.

Question 11

Accuracy

Answer 11

Describes how close the measurement is to its true value.

Question 12

Precision (2 definition)

Answer 12

Measure of reproducibility in a procedure by comparing percent variation.

It is also the size of the unit for the final significant figure.