Unit 1: Matter and Atomic Theories

Atoms with the same number of protons but different numbers of neutrons are known as:

• ions

• isotopes

• quarks

• none of the above

Atoms are neutral because they have: A) equal number of protons and neutrons B) equal number of electrons and neutrons C) equal number of protons and electrons D) equal number of quarks and protons.

• equal number of protons and neutrons

• equal number of electrons and neutrons

• equal number of protons and electrons

• equal number of quarks and protons

The smallest particle of an element that retains the properties of that element is a(n):

• electron

• atom

• neutron

• proton

• nucleus

The average mass of an element’s isotopes is its:

• Atomic number

• Mass number

• Atomic mass

The center-most part of an atom where the protons and neutrons are contained is the:

• A) electron cloud

• B) gluons

• C) nucleus

• D) group

Elemental particles with a mass = 1/1837 amu are:

• protons

• neutrons

• electrons

• atom

Physical combinations of two or more elements are:

• protons

• compounds

• mixtures

• isotopes

Equal to 1/12 the mass of a carbon-12 isotope:

• atomic mass unit (amu)

• atomic mass

• mass number

• atomic number

A mixture where the different components are visible.

• heterogenous

• covalent

• ionic

• homogeneous

Subatomic particles with a mass = 1 amu.

• protons

• quarks

• isotopes

• electron