question_answer

  Two elements are represented as and (a) Which of these elements will lose and gain electrons? (b) What is the number of electrons an atom loses, gains or shares called? (c) Write the electronic configurations of X And K       

Answer:

   (i) D and E have same mass number but different atomic numbers. Hence, they are a pair of isobars,         (ii) Electronic configuration of C is 2 (A), 5(7-). Hence, its valency is three because it gains three electrons to attain stable electronic configuration.                   (iii) For a neutral atom, Number of electrons = number of protons