Chapter 4 Vocab

Question 0

Dalton’s atomic theory

Answer 0

The first theory to relate chemical changes to events at the atomic level

Question 1

Atom

Answer 1

Smallest particle of an element that retains its identity in a chemical reaction

Question 2

Atomic mass

Answer 2

The weighted average of the masses of the isotopes of an element

Question 3

Atomic mass unit

Amu

Answer 3

A unit of mass equal to one twelfth the mass of a carbon-12 atom

Question 4

Atomic number

Answer 4

The number of protons in the nucleus of an atom of an element

Question 5

Cathode ray

Answer 5

A stream of electrons produced at the negative electrode of a tube containing a gas at low pressure.

Question 6

Electron

Answer 6

The simplest form of matter that has a unique set of properties; an element cannot be broken down into simpler substances by chemical means.

Question 7

Group

Answer 7

A vertical column of elements in the periodic table; the consistent elements of a group have a similar chemical and physical properties.

Question 8

Isotopes

Answer 8

Atoms of the same element that have the same atomic number but different atomic masses due to a different number of neutrons

Question 9

Mass number

Answer 9

The total number of protons and neutrons In the nucleus of an Atom

Question 10

Neutron

Answer 10

A subatomic particle with no charge and a mass of 1 amu; found in the nucleus of an atom

Question 11

Nucleus

Answer 11

The tiny, dense central portions of an atom, composed of protons and neutrons

Question 12

Period

Answer 12

A horizontal row of two elements in the periodic table

Question 13

Periodic table

Answer 13

An arrangement of elements in which the elements are separated into groups based on a set of repeating properties

Question 14

Proton

Answer 14

A positively charged subatomic particle found in the nucleus of an atom