1. 1.2 Ions
Understanding how electrons move inside an atom-how atoms react together-how has this helped develop artificial bones and wonder drugs?

2. Atoms and Ions
Remember atoms are neutral? Why same no. of electrons and protons
If we take an electron away or added…..they become charged as no longer equal
We called a charged atom …AN ION
Obviously if we remove an electron- POSITIVE CHARGE = cation
If we add an electron = NEGATIVE CHARGE - anion

3. CATIONS
Formed when an atom loses electrons usually from the outer shell- if it is empty more likely to form a cation
Most often an atom loses all its outer electrons so only full shells remain

4. Cations cont: Cations usually come from metal atoms
Metal atoms generally have few electrons in outermost shells so lose them easily as only weakly bound to the atom.

5. Non-metallic cations Or Mg2+ LOSES 2 ELECTRONS
Hydrogen can form cations whenever acids are dissolved in bases- acids and bases are our next topic and this will make more sense!
Cation symbols are made from the atomic symbol and the charge ie Na+ etc.
Or Mg2+ LOSES 2 ELECTRONS

6. ANIONS Produced when atoms gain electrons
Again occurs in outermost shell if it is almost full- it gains electrons until it is full
DRAW FROM PG 14 OF PEARSONS TEXT
All anions come from non-metallic atoms
Gain electrons in outer shell
Symbols used similar to cations-chemical symbol and charge Cl-

7. Ionic Compounds
When anions and cations come together they join in large compounds of crystal lattices
I.e Table salt NaCl
Naming ionic compounds is easy- its just the name of the cation followed by the anion
E.g, Sodium chloride
Chemical formula can be slightly more difficult-there must be an equal number of positive and negative charges so the total is neutral or Zero.

8. Chemical Formulas
In NaCl the charges are not shown as it is 1 positive and 1 negative so already is zero
Magnesium Chloride is more difficult
Magnesium has 2 positive charges and Chloride 1 Negative
Mg2+ and Cl –
To balance we need two Chloride ions so it is written as:
MgCl2

9. Ionic Bonding Cations and anions are attracted to one another……awwww
Due to the opposite charges
When the charged ions come together they “stick” to each other forming an ionic bond
These bonds hold together the crystal lattices:
Therefore they are:
Hard-need force to break
Brittle-bonds hold the lattice in fixed positions so will shatter before it bends
Have high melting points-it needs lots of heat/high temp to break the bonds and let the ions flow free
Ionic compounds are often bright colours

10. Ionic compounds

11. Ions in Solution Some compounds dissolve in water Some do not
How well the dissolve =their solubility
When ionic compounds dissolve they “charge” the water around them as they produce cations and anions-the lattice breaks apart, the ions can not re-join and they spread evenly in the solution
If the solution is heated to evaporation point they can re-join as the water is removed-re- crystallisation
When ions are in solution it can conduct electricity

12. Epsom salt crystal

13. practical
Pg 19
MAKING IONIC COMPOUNDS-
PRAC IN FOLDER