nucleus

the dense center of an atom that contains protons and neutrons

atom

the smallest unit of an element that has the same properties of that element

electron cloud

the area around the nucleus where electrons are most likely to be found

atomic mass

the average mass of the atoms of an element based on the naturally occurring isotopes

atomic structure

the way an atom is organized, including its protons neutrons, and electrons

energy level

a region around the nucleus where electrons are likely to be found

ion

an atom or group of atoms that has an electrical charge because it gained or lost electrons

subatomic particles

a particle smaller than an atom such as a proton ,neutron, or electron

chemical bond

the force that holds atoms together in a molecule or compound

chemical property

a characteristic that describes how a substance can react or change into a new substance

charge

an electrical property of matter that can be positive, or neutral

neutral atom

an atom that has an equal number of protons and electrons, giving it no overall charge

molecule

two or more atoms chemically joined together

periodic table

a chart that organizes elements according to their properties and atomic structure

proton

a positively charged particle found in the nucleus of an atom

electron

a negatively charged particle found in the space surrounding the nucleus

neutrons

a particle with no charge found in the nucleus of an atom

valence electron

an electron in the outermost energy level of involved in chemical reactions

isotope

atoms of the same element that have the same number of protons but different numbers of neutrons

matter

anything that has a mass takes up space

compound

a substance made when atoms of two or more different elements chemically combine

mass number

the total number of protons and neutrons in an atom

atomic number

the number of protons in an atoms nucleus. it identifies the element

element

a pure substance made of only one type of atom

physical property

a characteristic of a substance that can be observed or measured without creating a new substance