Matter Trends and Chemical Bonding
2.1
Ionic Compounds
Expectations: B2.1, B2.4, B2.6, B2.7, B3.4, B3.5
Learning Goals
• By the end of this class I will…
– Identify ionic compounds
– Break down the process of ionic bonding
– Derive chemical symbols for ions
– Derive ionic formulas
Last Class
• Identified periodic trends
– Atomic radii
– Ionization energy
– Electron affinity
Ionic Compounds
• Recall:
– A compound is a pure substance made up of 2 or
more elements.
– An ion is an atom or a group of atoms that have
either a positive charge or a negative charge
• An ionic compound is a compound that is
formed between cations and anions
Ionic Compounds
Properties
• Hard and Brittle
• High melting and boiling points
• Conduct electricity when
dissolved in water
– Solutions of ionic compounds in
water are called electrolytes
Ionic Bonding
• Ionic Compound = Metal + Non-metal
• In ionic bonding, a non-metal atom removes
an electron from a metal atom.
– Metal loses electrons to form a stable cation
– Non-metal gains electrons to form a stable anion
• The oppositely charged ions are attracted to
each other by electrostatic forces, which are
the basis of the ionic bond.
Ionic Bonding
• The result is a compound that has a neutral
charge
– EXAMPLE: Na+ + Cl- = NaCl (neutral)
**The total positive charge must balance**
the total negative charge
Ionic Formula
• Try together:
– calcium and chlorine
– lithium and nitrogen
– magnesium and oxygen
– magnesium and nitrogen
Drawing Chemical Symbols
Ions as Lewis Structures:
1. Draw square brackets around the ion
2. indicate the charge outside the brackets,
ie: Na+ and S2[Na]+
..
[ : S.. : ]2-
Drawing ionic Compounds
Draw the Lewis symbols to show the formation
of bonds between sodium and oxygen. Write the
chemical formula for the compound produced.
Drawing ionic Compounds
1. Write a Lewis symbol for each atom
Drawing ionic Compounds
1. Write a Lewis symbol for each atom
2. Decide on the ratio of ions required to
produce a neutral ionic compound
Drawing ionic Compounds
1. Write a Lewis symbol for each atom
2. Decide on the ratio of ions required to
produce a neutral ionic compound
3. Draw each ion as a Lewis symbol.
Drawing ionic Compounds
1. Write a Lewis symbol for each atom
2. Decide on the ratio of ions required to
produce a neutral ionic compound
3. Draw each ion as a Lewis symbol.
4. Write the chemical formula
Drawing Chemical Symbols
• Draw Lewis symbols to show the formation of
bonds and write the chemical formula for the
compounds
– calcium and chlorine
– magnesium and oxygen
– magnesium and nitrogen
Exit Ticket
Please complete and hand in before you go!
Draw Lewis symbols to show the formation of
bonds within calcium oxide. Write the chemical
formula for the compound produced.
Homework
Page 60
# 4, 7, 8