question_answer

  What information do you get from the figures about the atomic number, mass number and valency of atoms X, Y and Z? Give your answer in a tabular form.

Answer:

                   

	Atomic No.	Mass No.	Valency
X	5	11	3
Y	8	18	2
Z	15	31	3,5

    Mass number = No. of protons + No. of neutrons = 31 Number of neutrons = 31 - Number of protons                                      = 31 - 15 == 16