Science Wordwise chapter 4

dense, positively charged mass in the center of an atom

positively charged subatomic particle found in the nucleus

neutral subatomic particle found in the nucleus

Number of protons in an atom of an element
atomic number

sum of the protons and neutrons in the nucleus of an atom
mass number

atoms of the same element having different numbers of neutrons

possible energies that electrons in an atom can have
energy levels

Visual model of the most likely locations for electrons in an atom
electron cloud

Region of space where an electron is likely to be found

term for an atom whose electrons have the lowest possible energies
ground state