430 likes | 444 Views
Learn about ions, their formation, and ionic bonding. Discover how ions are charged particles and how atoms gain or lose electrons to form ions. Understand the properties of ionic compounds and the forces of attraction between ions in lattice structures.
E N D
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.
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
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 • 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