Lesson 1: Matter

atom

building block of matter; contains subatomic particles - neutrons, protons, and electrons

nucleus

the center of an atom; contains neutrons and protons

proton

a positively charged particle in an atom’s nucleus

neutron

a particle without charge in an atom’s nucleus

electron

a negatively charged particle that occupies space around an atom’s nucleus

element

a pure substance composed of only one type of atom; cannot be broken down into another substance by physical or chemical means

isotope

two or more atoms of the same element having different numbers of neutrons

compound

a purse substance with unique properties; formed when two or more different elements combine

covalent bond

a type of chemical bond formed when atoms share electrons

molecule

a compound whose atoms are held together by covalent bonds

ion

an atom that is positively or negatively charged because it has lost or gained electrons

ionic bond

an electrical attraction between two oppositely charged atoms or groups of atoms

Number of Protons

Determines which element an atom is

Atomic Number

the number of protons an element has, indicated on the periodic table of elements and defines the element’s identity

atomic mass

the mass of an atom (the total number of protons + neutrons)