List these words in your notebook. Find all definitions and write them out. Atomic number Mass number Atomic mass Isotope Proton Neutron Electron Endothermic Exothermic Phase changes Melting Freezing Condensation Vaporization Evaporation Boiling

Solids Definite shape? Yes Definite volume? Yes

Liquids Definite shape? No Definite volume? Yes

Gases Definite shape? Nope Definite volume? Nada

Plasma Definite shape? Nyet Definite volume? Uh uh…

Fill in the blanks from your list of definitions: The number of _______________ determines the element you have. This is also known as the element’s _________ __________. An element may have different number of ______________ within its nucleus. This is known as an ____________________ of an element. The _________ ______________ is the sum of the protons and neutrons in the nucleus of the atom.