chemical bonding concept

1. CHEMICAL BONDING
Grade 10 -(chapter 2)

2. CHEMICAL BONDING
Grade 10 -(chapter 2)
Learning objective::::
• What is a chemical bond?
• Why do atoms form chemical bond?
• How are the chemical bonds formed?
• Types of chemical bonds?
• Properties of each type of chemical
bonding..

3. CHEMICAL BONDING
Grade 10 -(chapter 2)
Prior knowledge check:::
• Periodic table
• Metals and non-metals
• Noble gases
• Electronic configuration
• Octet rule

4. Electron Configuration
1st level = max 2 electrons
2nd level = max 8 electrons
3rd level = max 8 electrons
Start filling from the inside out.
You cannot move up until a level is
filled.

6. Why do Atoms React?
Themoststablearrangementofelectrons inanatom
istohaveeitherafilled valence shell ortohave8
valence electrons (octetrule).
Atomsobtainthisstableelectron arrangementby
sharing,gainingorlosingelectrons –whichiswhat
creates chemical bonds.
• To get a full outer shell of electrons!

9. Types of Chemical Bonds
There are three major types of
chemical bonds:
•ionic bonding
•covalent bonding
•metallic bonding
The type of bond formed depends on
the ionization energy and
electronegativity of the atoms involved

10. The Ionic Bond
When an atom with a high EN is placed near an atom
with a low IE, the first atom may “steal” an electron
from the second atom.
The atom that gives up the electron becomes a
positively charged cation, and the atom that gains
the electron becomes a negatively charged anion.
An ionic bond is the “electrostatic” attraction
formed between the oppositely charged cation and
anion.
Properties of Ionic Compounds
Ionic Bonding
Definite crystalline structure
High melting points
Brittle as solids
Most dissolve in water
Conduct electricity only when in the molten state or
when dissolved in water.

11. Ionic bonding

12. Sodium and chlorine

13. Covalent bond
• The electrostatic force of attraction
between the nuclei of bonded atoms and
the shared pair of electrons
+ +
Shared pair or bonding
electrons
 Covalent bond forms when pairs of electrons are shared by atoms.
 The shared electrons (bonding electrons) lie in the space between the
atoms.

15. 2. Covalent bonds- Two atoms share one or more pairs of outer-shell
electrons.
Oxygen Atom Oxygen Atom
Oxygen Molecule (O2)

16. Drawing ionic compounds using
Lewis Dot Structures
• Symbol represents the KERNEL of the
atom (nucleus and inner e-)
• dots represent valence e-

17. NaCl
• This is the finished Lewis Dot
Structure
[Na]+ [ Cl ]
-
How did we get here?

18. • Step 1 after checking that it is IONIC
– Determine which atom will be the +ion
– Determine which atom will be the - ion
• Step 2
– Write the symbol for the + ion first.
• NO DOTS
– Draw the e- dot diagram for the – ion
• COMPLETE outer shell
• Step 3
– Enclose both in brackets and show each
charge

19. Draw the Lewis Diagrams
• LiF
• MgO
• CaCl2
• K2S