4 Full energy levelsWhen the outermost energy level of an atom is filled with electrons, the atom is stable and not likely to react.Nobel gases have stable electron configurations with eight valence electrons
5 Stable or not, Ions come!!Elements that do not have complete sets of valence electrons tend to react.
6 Ionic BondingSome elements achieve stability through the transfer (give away) of electrons between atoms.
13 Ionization EnergyAn electron can move to a higher energy level when an atom absorbs energy.The energy allows electrons to overcome the attraction of the protons in the nucleus.The amount of energy used to remove an electron is called ionization energy.It varies from element to element.The lower the ionization energy, the easier it is to remove an electron from an atom.
22 MoleculeA neutral group of atoms that are joined together by one or more covalent bonds.
23 Chemical FormulaUsed to describe the molecules of an element as well as a compound.The element hydrogen has the chemical formula H2.The subscript 2 indicates that there are two atoms in a molecule of hydrogen.