Chemistry Chapter 1 - Kory Parsia

proton

A positively charged particle located in an atom's nucleus

neutron

A particle that has no electric charge and is located in an atom's nucleus

nucleus

The central region of an atom where most of the atom's mass is found in protons and neutrons

electron

A negatively charged particle located outside an atom's nucleus. An electron is about 2000 times smaller than either a proton or neutron

atomic number

The number of protons in the nucleus of an atom

atomic mass number

The total number of protons and neutrons in an atom's nucleus

isotope

An atom of one element that has a different number of neutrons than another atom of the same element

ion

An atom or group of atoms that has a positive or negative electric charge

atomic mass

The average mass of the atoms of an element

periodic table

A table of the elements, arranged by atomic number, that shows the patterns in their properties

group

A vertical column in the periodic table of the elements. Elements in a group have similar properties

period

A horizontal row in the periodic table of the elements. Elements in a period have varying properties

reactive

Likely to undergo a chemical change

metal

An element that tends to be shiny, easily shaped, and a good conductor of electricity and heat

nonmetal

An element that is not a metal and has properties generally opposite to those of a metal

metalloid

An element that has properties of both metals and nonmetals

radioactivity

The process by which the nucleus of an atom of an element releases energy and particles

half-life

The amount of time it takes for half of the nuclei of a radioactive isotope to decay into atoms of another element