Ionic Compounds and Bonding SNC2D – Academic Science

Learning Goals  Use Lewis dot diagrams to illustrate how a compound forms between a metal and a non-metal.

Ions are formed when electrons are gained or lost  Where do electrons that are lost go?  Where do the electrons that are gained come from?

Ionic Bonding  An ion is an atom that develops a charge after gaining or losing electrons.  Ionic bonding occurs between a metal and a non- metal element.  The metal ion loses its electron(s) and becomes positive !  Cation : a positively charged ion  The non-metal ion gains electron(s) and becomes negative !  Anion : a negatively charged ion

Ionic Bonding  The ions that are formed have a completed (full) outer energy level.  When the ions bond together, the overall charge of the compound is neutral.  Example  Sodium+Chlorine  Sodium chloride

Chemical Formulas  The chemical formula is a combination of symbols that represent a particular compound. It indicates which elements are present and the number of atoms of each element found in the compound.  Example  Calcium+Chlorine  Calcium chloride

Ionic Compounds  An ionic compound is a compound consisting of positive cations and negative anions that have resulted from the transfer of electrons from a metal to a non-metal.  The metal loses electrons and the non-metal gains electrons resulting in an overall charge of zero. metal +non-metal  ionic compound

Ionic Compounds  Positive and negative ions are attracted to each other making the compound stable.  Ionic compounds are electrolytes, meaning that when dissolved in water, the ions separate and move freely to conduct electricity.