Atoms and Ions

Atomic Mass - Number of Protons + NeutronsAtomic Number - Number of Protons (Also number of electrons)Atomic mass is always the largest number on a chemical element, Atomic number is smaller.DRAWING ELEMENTS-Inner electron shell always only has 2 electrons-Next two shells can hold 8-Fourth can hold 16The group numbers go down the periodic tableGroup # Is the amount of electrons in outermost shellPeriod numbers go across the tablePeriod # is the amount of shellsIONSIons have an electrical charge (+) or (-)Imbalance in Protons and ElectronsWhen writings chemical formulae for ionic compounds, positive compound goes first (e.g AlBr3)A full outer shell = Stable AtomAn atom with 6 electrons on its outer shell can gain 2 electrons from 2 atoms with 1 electron on its outer shell, to form an ionic compound.Ionic Compounds have no charge.