Page 2 - PRACTICE WORKSHEET
P. 2

Q.8. (a) The electronic configuration of phosphorus atom is 2, 8, 5. Give the electronic
                                  3-
               configuration of P  ion.
               (b) The atomic number of Al and Cl are 13 and 17, respectively. What will be the
                                          3+
                                                   –
               number of electrons in Al  and Cl ?

               Q.9 .(a) Calculate the number of neutrons present in the nucleus of an element X which
               is represented as
               (b) Why do isotopes show similar chemical properties?
               Q.10. (a) List any three distinguishing features between the models of an atom
               proposed by J.J. Thomson and Ernest Rutherford.

                (b) Predict the valency of the following elements
                   (i) A (Atomic number 5)
                   (ii) B (Atomic number 12)
                   (iii) C (Atomic number 14)
                   (iv) D (Atomic number 17)









































               2
   1   2