The atomic number of chlorine is 17. What is the number of electrons in CI-?

5 What do we call those particles which have less electrons than the normal atoms? 6 The atomic number of sodium is 11. What is the number of electrons in Na+? 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) magnesium atom, and

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