entire chapter of chemical bonding icse std 10

1. Chemical bondingWHAT IS BOND?
CHEMICAL BOND IS THE FORCE WHICH HOLDS TWO OR MORE ATOMS TOGETHER IN
A STABLE MOLECULE.

2. Methods of achieving chemical bonding:
 Electron transfer:of valence electron from one atom to another
atom,forming electrovalent bond or ionic bond
 Electron sharing of pairs electrons between the reacting
atoms,leading to formation of covalent bond.
• octet rule
In forming compounds, atoms tend to gain or lose electrons in order to achieve the
electron configuration of a noble gas!!!

3.  Octet Rule = atoms tend to gain, lose or share electrons so as
 to have 8 electrons

4. Formation of cation:
 When an atom loses an electron it
 produces a positively charged ion, or a
cation.
 • The most common cations are those
 produced by the loss of valence electrons
 from metal atoms.

5. Formation of Anions
 The gain of negatively
 charged electrons by
 a neutral atom
 produces an anion.

6. Electron-Dot Structures
• Valence electrons represented by dots
• Electron-dot symbols
– Examples: Na•, •Mg•, …

7. Types of bonding
ELECTROVALENT BOND
COVALENT BOND
CO-ORDINATE BOND

8. Electrovalent bond or Ionic bond

9. Structure of some electrovalent compound
 NaCl:

10. Magnesium chloride

11. CaO

12. COVALENT COMPOUNDS
Properties
1) Covalent compounds generally have much
lower melting and boiling points than ionic
compounds.
2) Covalent compounds are soft and squishy
(compared to ionic compounds, anyway
On the other hand, covalent compounds have these
molecules which can very easily move around
each other, because there are no bonds between
them. As a result, covalent compounds are
frequently flexible rather than hard.

13. 3) Covalent compounds tend to be more
flammable than ionic compounds.
4) Covalent compounds don't conduct
electricity in water.
5) Covalent compounds aren't usually
very soluble in water.
Covalent Bonds are atoms held together
by
SHARING electrons between
NONMETALS

14. Covalent Bonding
 Remember that ionic compounds transfer electron in order to attain
Nobel gas electronic configuration
 Covalent compounds form by sharing of electrons to attain nobel
gas configuration
 Regardless of the type of bond, the Octet rule still must be obeyed.

15. Single Covalent Bond
 A Single Covalent Bond consists of two atoms held together by
sharing 1 pair of electrons (2 e-)

16. Electron Dot Structure

17. Double Covalent Bonds
 Sometimes atoms attain noble gas configuration by sharing 2 or 3
pairs of electrons
 A Double Covalent Bond is a bond that involves 2 shared pairs of
electrons (4 e-)

18. Triple Covalent Bond
 A Triple Covalent Bond is a bond that involves 3 shared pairs of
electrons (6 e-)

19. Polar Bonds and Molecules
 There are two types of covalent bonds
 Nonpolar Covalent Bonds (share equally)
 Polar Covalent Bonds (share unequally)
Polar Covalent
 A Polar Covalent Bond is unequal sharing of electrons between two
atoms (HCl)
 • In a polar covalent bond, one atom typically has a negative
charge, and the other atom has a positive charge

20. Nonpolar Covalent Bond
 A Nonpolar Covalent Bond is equal sharing of electrons between
two atoms (Cl2, N2, O2)
 No charge separation takes place. The covalent molecule is
symmetrical and electrically neutral.

21. Difference b/w ionic and covalent
compound

23. Co-ordinate bond or Dative Bond
 Type of covalency which involve one of the combining atoms
contributing both of the shared electron.
 i.e a bond formed by a shared pair of electrons with both electrons
coming from the same atoms.
 E.g: Ammonium chloride

24. Formation of Hydronium ion
+
↓
Or

25. Formation of Ammonium ion
+
↓
Or

26.  THANK YOU
By
Sudipa Bhattacharjee