S2 Science Ions and Ionic Bonding

Learning Outcomes We are Learning about ionic bonding

Success Criteria I can describe what an ion is and describe their formation I can describe an ionic bond and explain that it usually consists of a metal/non-metal combination I can state that ionic substances form lattice structures I can state that the forces of attraction between oppositely charged ions in a lattice structure are strong I can state the properties of ionic compounds

Ions Ions are charged particles

Ions Ions are charged particles The simplest ions are atoms that have lost or gained electrons

Ions Ions are charged particles The simplest ions are atoms that have lost or gained electrons Atoms lose or gain electrons to become like the noble gasses

Why Ions Form The lithium atom has the electron configuration 2,1 The target diagram would be - Li 3+ 2,1

Why Ions Form To achieve the stable electron arrangement of the noble gas the lithium atom would have to lose its outer electron.

Why Ions Form The lithium ion has the electron configuration of just 2 The target diagram would be - 3+ 2 Li+

Why Ions Form The lithium ion now has the same electron configuration as helium and so is very stable.

Why Ions Form It has 3 protons but only 2 electrons The extra proton gives it a positive charge.

Why Ions Form The fluorine atom has 7 electrons in its outer shell The target diagram would be - 9+ 2,7 F

Why Ions Form To become like the noble gases it must either lose or gain electrons.

Why Ions Form To become like the noble gases it must either lose or gain electrons. It cannot lose 7 electrons so it must gain just 1 to complete the shell

Why Ions Form The fluoride ion has 8 electrons in its outer shell The target diagram would be - 9+ 2,8 F-

Why Ions Form The fluorine ion has 10 electrons and 9 protons.

Why Ions Form The fluoride ion has 10 electrons and 9 protons. The extra electron gives it a negative charge.

Ions Summary Metals lose electrons to form positive ions.

Ions Summary Metals lose electrons to form positive ions. Non metals gain electrons to become negative ions.

Ions Summary Metals lose electrons to form positive ions. Non metals gain electrons to become negative ions. Metal and non-metal ions attract each other to form ionic compounds

Ions Summary Metals lose electrons to form positive ions. Non metals gain electrons to become negative ions. Metal and non-metal ions attract each other to form ionic compounds The attraction between positive and negative ions is called the ionic bond.

Ions Summary Group Number 1 2 3 4 5 6 7 8 Valency/combining power Charge on the ion

Ions Summary Group Number 1 2 3 4 5 6 7 8 Valency/combining power Charge on the ion

Ions Summary Group Number 1 2 3 4 5 6 7 8 Valency/combining power Charge on the ion 1+ 2+ 3+ 3- 2- 1-

The Ionic Bond Sodium chloride is a typical ionic compound Sodium forms a positive ion Na+ Chlorine forms a negative ion Cl- The negative chloride ion is attracted strongly to the positive sodium ion

Solid, liquid or solution Conductivity tests Substance Solid, liquid or solution conductor iron solid sugar solution Sodium chloride water liquid Copper sulphate ethanol Zinc chloride Zinc iodide

Solid, liquid or solution Conductivity tests Substance Solid, liquid or solution conductor iron solid  sugar solution Sodium chloride water liquid Copper sulphate ethanol Zinc chloride Zinc iodide

Conductivity tests Compounds which contain only non metals do not conduct electricity.

Conductivity tests All metals conduct electricity

Conductivity tests All metals conduct electricity Compounds containing metals do not conduct when solid but do conduct when molten or in solution

Conductivity tests All metals conduct electricity Compounds containing metals do not conduct when solid but do conduct when molten or in solution These compounds are called ionic compounds

Compounds Ionic compounds contain ions

Compounds Ionic compounds contain ions Only when the ions can move freely will the compound conduct electricity

Compounds Ionic compounds contain ions Only when the ions can move freely will the compound conduct electricity In a solid the ions cannot move and so cannot conduct electricity

Electrolysis Electrolysis means the breaking up of a compound by the action of electricity. (‘electro’ = electricity; ‘lysis’ = breaking apart)

Electrolysis DC Carbon electrodes copper chloride

Electrolysis of copper chloride Observations Made At positive rod At negative rod

Electrolysis of copper chloride Observations Made At positive rod At negative rod Colourless gas Brown solid

Electrolysis of copper chloride The metal copper was formed at the negative rod The gas chlorine was formed at the positive rod.

Ions on the move An electrolyte is a liquid or solution that conducts electricity by ions moving through it. An electrode is a rod where the electricity enters or leaves the electrolyte.

Ions on the move The ions always move towards oppositely charged electrodes.

Ions on the move The ions always move towards oppositely charged electrodes. Positive metal ions move towards the negative electrode

Ions on the move The ions always move towards oppositely charged electrodes. Positive metal ions move towards the negative electrode Negative non metal ions move towards the positive electrode