Atom Notes Adapted from Harris Middle School: NEISD Name: _____________________________________ _______________: chart where all elements are arranged by ________________and ____________-this is your cheat sheet to make models of atoms!! An __________________ is the basic unit of all matter. It is the smallest particle into which an __________ cannot be broken down into a simpler substance. There are 2 main locations in an atom: ______________(the center with most of the mass of the atom) _____________ (surrounds the nucleus) There are 3 subatomic particles in an atom: subatomic means smaller (than the atom itself) 3 particles = ___________, ___________, and_________ the numbers of these particles make atoms __________ from one another. _______________= # of protons = element’s identity _______________= # of protons in an atom (neutral) ______________is 1 or 2 letters- First letter is always capitalized; if it has 2 letters the second is lower case _______________= # of protons + # of neutrons _______________= atomic mass – atomic # atoms of an element can have different numbers of neutrons (these atoms are_________________) Name of subatomic particle Charge of Particle Where it is found Size/mass proton inside the nucleus- identifies the atom Negative (-) in electron cloud / orbiting around nucleus- determines reactivity of element Almost zero 1/1836 amu (very small!) neutron Neutral (0) 1 atomic mass unit Label the subatomic particles in the picture: p+ = proton n0 = neutron e- = electron Color the neutrons red Color the electrons green