AtomBasic Component

of Matter

Electrons Negatively charged

particles

NucleusTiny, massive core containing protons

and neutrons

ProtonsPositively charged particles

in an atom’s nucleus

Made of 3 quarks

Energy Level Specific amount of energy

an electron has

Neutron Particles in the nucleus of

an atom that has no electric charge

Atomic NumberNumber of protons in

nucleus of an atom

Isotopes Atoms of the same element but have a different amount of

neutrons

Mass NumberThe sum of the protons

and neutrons in the nucleus. Note: a whole number because it refers to specific atom.

Atomic MassAverage mass of all

isotopes

Periodic Table Arrangement of elements

showing repeating pattern of elements

Periods Horizontal rows in the periodic table

Groups Vertical columns of the periodic table

Chemical Symbol Symbol of an element

using letters

Metals

An element that is a conductor of heat

MalleableMaterial that can be

hammered, rolled into flat sheets, or shaped

DuctileMaterial that can be pulled

out into a long wire

Thermal Conductivity Ability of an object to

transfer heat

Electrical Conductivity

Ability of an object to transfer electricity

Reactivity The speed which a substance reacts with other substances

CorrosionGradual wearing wearing of a

metal because of chemical reaction

Alkali Metals Metals in group one of the

periodic table

Alkaline Earth Metals

Group two of the periodic table

Transition Metals Elements in group three to group

twelve on the periodic table

Particle AcceleratorsPowerful machines that move

atomic nuclei really fast

Nonmetal Elements that lack most

properties of metal

Diatomic Molecule

Molecule that consists of two atoms

HalogensGroup 17 of the periodic

table

Inert Gases

Group 18 of the periodic table

Semimetals

Elements that have some metal and have some properties that are

nonmetal

Semiconductors Substances that can conduct an electric current under some circumstances and

cannot in some circumstances

Radioactive Decay Atomic nuclei of isotopes

release fast-moving particles and energy

Radioactivity Property that is able

to emit radiation

Alpha Particle

Consists of two neutrons and two protons and is positively

charged

Beta Particle Fast moving electron that is given off by a nucleus during radioactive

decay

Gamma Radiation

High energy waves

TracersRadioactive isotopes that can be

followed using a detector

MoleculeTwo or more atoms

joined in chem. bond

CompoundA pure substance made of

two or more elements chemically combined