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KS4 Chemistry. Ionic Bonding. Full electron shells. 2 nd shell holds a maximum of 8 electrons. 1 st shell holds a maximum of 2 electrons. 3 rd shell holds a maximum of 8 electrons.
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KS4 Chemistry Ionic Bonding
Full electron shells 2nd shell holdsa maximum of8 electrons 1st shell holdsa maximum of2 electrons 3rd shell holdsa maximum of8 electrons Atoms of noble gases, group 8, have completely full outer shells. This makes them very unreactive or stable.
Atoms and electron changes Every atom would like to have a full outer shell like the noble gases. Atoms can get full outer electron shells by either gaining or losing electrons
From atoms to ions How can reactive metal atoms become stable positive ions?
Bonding: example 1 Making sodium chloride – table salt!!!
What would a chlorine atom have to do to have a stable electron configuration like a noble gas? It will have to gain an electron!!!
What would a sodium atom have to do to have a stable electron configuration like a noble gas? It will have to lose an electron!!!
Can you think of a way that chlorine could gain an electron and sodium could lose an electron?
Once this happens both of the atoms will now be ions and will each have a charge!!
The oppositely charged ions attract each other and form an ionic bond!!
Key definitions An ionic bond is formed when ions that have opposite charges attract
Ionic lattices - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + In an ionic compound, millions and millions of ions are packed all joined by ionic bonds - - - + + + - - - + + + - - - + + + - - - + + + - - - + + +
Bonding example 2 Making Magnesium oxide
What would magnesium need to do to get a stable full outer shell? Mg
O What would oxygen need to do to get a stable full outer shell?
Can you think of a way that Magnesium could lose two electrons and oxygen could gain two electrons? O Mg Magnesium gives two electrons to oxygen!
Once this happens the Magnesium and Oxygen atoms each get charge and become ions of opposite charge 2+ 2- O Mg [2.8]2+ [2.8]2- 2.8.2 2.6
Magnesium oxide: part 2 O Mg The positive magnesium ions and the negative oxygen ions are strongly attracted to each other and form an ionic bond. -2 +2
Ionic lattices - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + - - - - - - + + + + + + In an ionic compound, millions and millions of ions are packed together in a regular cubic arrangement, joined by ionic bonds.. - - - + + + - - - + + + - - - + + + - - - + + + - - - + + +
Compounds H O H Compounds are made up of two OR MORE different elements chemically combined Example: water – H20 Others compounds, like DNA, have large, complex structures containing thousands or even millions of bonded atoms.