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At the end of this lesson we will be able to understand :-
Why an atom gets bonded with other atom or atoms.
Different types of solids depending upon type ofbonding between their particles.
Properties of different solids.
Group zero elements
Element Electronic configuration
Behavior of atoms
2He4 2 Helium atoms do not bond
10Ne20 2 , 8 Neon atoms do not bond
18Ar40 2 ,8, 8 Argon atoms do not bond
Argon: 18Ar40
Nucleus
First shell: 2electrons
Second shell : 8 electrons
Third shell : 8 electrons
Each shell is full .
Magnesium :12 Mg24
Nucleus
First shell ; 2 electrons
Second shell : 8 electrons
Third shell : 2 electrons
Outer shell not full : only 2 electrons in it
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Now I am sure you can tell me that why bonding takes place between two atoms.
Types of solidsDepending on the type of bonding solids
are of Four types –
Molecular solids Macromolecular solids Metallic solids Ionic solids
C C
C
C
C
Carbon is in IV group –each atom has 4 outer shell electron
Carbon (diamond) : a macromolecular solid
Carbon lattice
The whole lattice is held together by covalent bonds. These are strong forces of attraction, so a considerable amount of energy is needed to break up the lattice.
Lattice of iodine molecules
The forces of attraction between molecules is weak , however – they all have full shells – so lattice is easily broken up.
sodium atom Na
sodium ion Na+
11 protons, 11 electrons: neutral 11 protons, 10 electrons:+ charged
Sodium : a metallic solid
Removed electron
delocalized electrons moving though the lattice carrying negative charge
Metals conduct electricity well
repel
Force applied
Although ionic solids are hard , they are brittle. They shatter when hit by a hammer.
Summary• Properties of a solid depend on the type of particle
in the lattice & the way in which they attract each other in the lattice.
• There are three types of bonding – covalent bonding, metallic bonding, ionic bonding .
• In all these bonding, the atoms achieve full electron shells .
• An ion is a particle which has gained or lost electrons, so is charged .
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