CHEMICAL BOND

Name: Assignment - II Class: X Subject: Chemistry

CHEMICAL BOND


I Choose the correct answer

1. Octet configuration means ( )
(a) Having 6 valence electrons (b) Having 4 valence electrons
(c) Having 8 valence electrons (d) Having 2 valence electrons
2. At critical inter nuclear distance, the potential energy of the combining atoms is ( )
(a) Minimum (b) Maximum (c) It does not change
(d) Some times it is minimum and some times it is maximum.
3. Complete transfer of electrons from one atom to another leads to the formation of ( )
(a) Covalent bond (b) Polar covalent bond (c) Ionic Bond (d) None
4. Polar covalent bond is present in ( )
(a) Cl2 (b) H2 (c) F2 (d) HCl
5. Sharing of electrons lead to the formation of ( )
(a) Ionic bond (b) Covalent bond (c) Hydrogen bond (d) Metallic bond
6. If two pairs of electrons are shared between two atoms, that bond is called ( )
(a) Ionic bond (b) Co-ordinate covalent bond (c) Double bond
(d) Triple bond
7. If both the shared pair of electrons are contributed by only one atom it is called ( )
(a) Ionic bond (b) Covalent bond (c) Polar covalent bond (d) Co-ordinate covalent bond
8. Shape of H2O is ( )
(a) ‘V’ Shape (b) Pyramidal (c) Linear (d) Tetrahedral
9. Shape NH3 is ( )
(a) Linear (b) ‘V’ Shape (c) Tetrahedral (d) Pyramidal
10. Shape of PCl2 is ( )
(a) Linear (b) Trigonal bipyramidal (c) Tetrahedral (d) Pyramidal
11. Shape of BeCl2 is ( )
(a) Tetrahedral (b) Pyramidal (c) Linear (d) ‘V’ Shape
12. s-p overlap is present in ( )
(a) HCl (b) O2 (c) Cl2 (d) H2
13. p-p overlap is present in ( )
(a) HCl (b) Cl2 (c) BeCl2 (d) NH2
14. Triple bond is present in ( )
(a) Cl2 (b) H2 (c) CaCl2 (d) CaC2




15. The essential condition for the overlap of orbitals is that ( )
(a) They must be completely filled orbitals
(b) They must be only ‘s’ orbitals
(c) They must be half filled valence orbitals
(d) They must be only ‘p’ orbitals.

II Fill in the blanks

1. s-s overlap always leads to the formation of __________________ bond
2. End – on – end overlap of two orbitals always leads to the formation of ___________ bond
3. Side – on – side overlap of orbitals leads to the formation of _________________ bond
4.  - bond can exist ___________________
5.  - bond can’t exist ____________________
6. C2H2 has ___________________ bonds and __________________ bonds
7. N2 has _____________________ and _____________________ bonds
8. Oxygen has __________________ lone pairs of electrons in H2O molecule.
9. Nitrogen has __________________ lone pair of electrons in NH3 molecule.
10. ________________ atom is donor in (H3O)+
11. ________________ is acceptor in NH3.BF3

III 1 Mark questions

1. Name a molecule having s-s overlap.
A. Hydrogen
2. Name molecules having s-p overlap
A. HCl, H2O, NH3, HBr, HI, H2S
3. Name three molecules having p-p overlap
A. Cl2, O2, N2, Br2
4. Which orbitals can form ‘’ bond?
A. Side – on – side overlap of p-p orbitals can form  bond. [s orbitals are never involved in the formation of  bond]
5. Which orbitals can form  bond?
A. Overlap of s-s orbitals, end-on-end overlap of s-p, or p-p orbitals can form  bond.
6. Name the molecules that are linear in shape.
A. CO2, BeCl2 and HCN molecules have linear shape.
7. Name the molecules that have pyramidal shape.
A. Ammonia (NH3), Phosphorus trichloride (PCl3) and phosphine (PH3) have pyramidal shape.



8. Which molecules have triple bonds?
A. Acetylene (C2H2), Nitrogen (N2), Calcium Carbide (CaC2), Hydrogen Cyanide (HCN) have triple bonds.
9. Which molecules have double bonds in them?
A. Carbon dioxide (CO2), Oxygen (O2) and Ethylene (C2H4) have double bonds.
10. Which molecules have co-ordinate covalent bond?
A. Ammonia boron trifluoride (NH3BF3), Ammonium ion (NH4+), Hydronium ion (H3O+), Hexa hydrate iron (II) ion [Fe(H2O)6+2], Hexahydrate copper (II) ion [Cu(H2O)6]+2

IV 2 Marks questions

1. Explain how covalent bond is formed?
2. Explain the formation of HCl molecule by overlapping of orbitals?
3. Explain the formation of HCl molecule by electron dot formula?

V 4 Marks questions

1. Discuss the types of overlaps that are possible with s and p orbitals?
2. Explain the formation of a double bond.
3. Explain the formation of a triple bond.
4. Explain the formation of co-ordinate covalent bond.

VI 5 marks questions

1. Draw the neat diagrams how sigma and pi bonds are formed.
2. Draw the shapes of H2O, NH3 and PCl5