Transcript Ionic B - Kapiti College

Ionic Bonding
Keywords:
Ionic Bonds, Salts, Lattice
Objectives:
1. The formula of an ionic compound
depends on the number of electrons
gained or lost by the elements that make
it up.
2. Use dot and cross diagrams to show
what happens when ionic compounds are
formed.
Ionic bonding
This is where a metal bonds with a non-metal (usually). Instead
of sharing the electrons one of the atoms “_____” one or more
electrons to the other. For example, consider sodium and
chlorine:
Na
Sodium has 1 electron on its outer shell
and chlorine has 7, so if sodium gives
its electron to chlorine they both have
a ___ outer shell and are ______.
+
A _______
charged
sodium ion
Na
Cl
Cl
A _________
charged
chloride ion
Some examples
Magnesium
chloride:
Mg
Cl
-
2+
+
Mg
-
Cl
Cl
MgCl2
Calcium oxide:
Ca
+
Cl
2+
O
Ca
2-
O
CaO
Ionic Bonding Practise
Magnesium Oxide Formation: MgO
Mg
(2,8,2)
+
2+
2-
O
Mg
O
(2,6)
(2,8)2+
(2,8) 2-
Using electron dot diagrams write the equation
for formation of the following ionic
compounds:
1. Potassium Fluoride
2. Sodium Bromide
3. Aluminium Oxide
4. Barium Chloride
5. Aluminium Chloride
Ionic Compounds
Held together by strong electrostatic forces
• Opposite charges attract
• High melting points and boiling points
• Regular structures – giant ionic lattices
• When melted or
dissolved ionic
compounds conduct
electricity
Ionic Lattice
Sodium chloride
A giant ionic lattice with
_____ melting and boiling
points due to ______ forces
of attraction.
Ionic substances can conduct
electricity when _______
because the ions are free to
move around.
Moving charges is electricity.
Homework exam questions
Due: Tomorrows lesson
Question 1 (Achieved level)
For each of the following elements or compounds:
(a) Find total number of valance electrons in the molecule
(b) Draw a Lewis structure (electron dot diagram)
1. NH3
2. H2O
3.O2
4.BF3
5.F2
6.Cl2O
Question 2 (Merit level)
For each of the following draw the Lewis structure:
1.H2S
2.PCl3
3.CH3Br
4.COCL (C is the central atom)
Ionic Bond Recap
• When an electron completely
transfers from one atom to another.
• The electrostatic attraction a
positively charged ion and a
negatively charged ion is called an
ionic bond
• When many ionic molecules line up
in a together it is an ionic lattice