1. Ionic Bonding

2. Ionic Bond Electrostatic attraction that holds ions together
Electrostatic force – like charges repel, opposite charges attract
How do we get ionic bonds?
When an atom gains an electron its called?
When an atom loses an electron its called?
Electrostatic force tells us that cations and anions should?
Can an ionic bond consist of two anions or cations?

3. Cations
Atom or group of atoms with a positive charge from the loss of valence electron(s)
Ca “+” ion
All metals are cations
Reactivity is based on the ease in which they lose a valence electron
What do metals do in order to achieve a stable octet?
If a metal is very reactive will it have high or low ionization energy?

4. Na atom Na
1s22s22p63s1
Na ion (lost 1 electron)
Na+
1s22s22p6
Mg atom Mg
1s22s22p63s2
Mg ion (lost 2 electrons)
Mg2+
Al atom Al
1s22s22p63s23p1
Al ion (lost 3 electrons)
Al3+
Ne atom (noble gas) Ne

5. Anions
Atom or group of atoms with a negative charge from the gain electron(s)
Tend to be nonmetals
Cl atom Cl
1s22s22p63s23p5
Cl ion (gain 1 electron)
Cl-
1s22s22p63s23p6
S atom S
1s22s22p63s23p4
S ion (gain 2 electrons)
S2-
Ar atom Ar
If atoms lost electrons to become positive, what do you think atoms do to become negative?
What kind of electrons are gained?
Why are they gaining electrons?

6. Monatomic Ions +1 +2 +3 -3 -2 -1

8. We can use our lewis dot diagrams in an equation to model ionic bonding

9. Ionic Compounds Held together by ionic bonds Composed of ions
Cation and anion
Usually a metal and nonmetal
Electrically neutral
Ex: salts

10. Formula Unit
Lowest whole-number ratio of ions that form form an ionic compound
The cation is always written before the anion
Ionic compounds carry what charge?
So this means our cations and anions have to do what?

11. Atoms Cation Anion Ratio Formula Unit Na and Cl Na+ Cl− 1:1 NaCl
Mg and O
Mg2+
O2−
MgO
Na and O
2:1
Na2O
Al and Br
Al3+
Br−
1:3
AlBr3
Ionic compounds are electrically what?
**Total positive charge of the cations equals the total negative charge of the anions

12. Example 1
Predict the compound formed when magnesium and nitrogen combine.
Start with the atoms
Write their ions
Crisscross charges to get neutral compound
Write formula unit Mg N
Mg2+
N3−
Mg3N2

13. Example 2
Predict the compound formed when magnesium and nitrate combine.
Start with the atoms
Write their ions
Crisscross charges to get neutral compound
Write formula unit Mg
NO3
Mg2+
NO3−
Mg(NO3)2

14. Properties Strong bonds High melting and boiling points
Solid at room temperature
Hard, rigid, and brittle
When dissolved in water or melted it can conduct an electric current

15. Electrolyte Salt dissolving in water animation
All stalts are ionic compounds but not all ionic compounds are salts

16. Crystal Lattice Structure of ionic compounds
Repeating 3-D pattern (alternating cation & anion)
Large attractive forces result in a very stable structure
Where do these attractive forces come from?