Write down the electronic configuration of

(i) magnesium atom, and

(ii) magnesium ion. (At. No. of Mg = 12)

6 The atomic number of chlorine is 17. What is the number of electrons in CI-? 7 The atomic number of an element X is 8 and that of element Y is 12. Write downthe symbols of the ions you would expect to be formed from their atoms. 8 Write down the electronic configuration of

(i) sulphur atom, and

(ii) sulphide ion. (At. No. of S = 16)

9 What type of chemical bonds are present in a solid compound which has a high melting point, does not conduct electricity in the solid state but becomes a good conductor in the molten state ?