A species ‘X’ contains 20 protons and 18 electrons. (A) species ‘Y’ contains 18 protons and 18 electrons. What are ‘X’ and ‘Y’ respectively ?

A species ‘X’ contains 20 protons and 18 electrons. (A) species �

1.	A species ‘X’ contains 20 protons and 18 electrons. (A) species ‘Y’ contains 18 protons and 18 electrons. What are ‘X’ and ‘Y’ respectively ?
Answer» CA and Ar `Ca^(2+)` and `S^(2-)` `Ca^(2+)` and `CI^(-)` `Ca^(2+)` and Ar Solution :(i) X has 20 protons `therefore` ATOMIC number = Z = 20`therefore`The atom is Ca But it has 18 electrons `therefore` X MUST be `Ca^(2+)` (II) Y has 18 protons `therefore`atomic number = 18 = Z `therefore` The atom is Ar But no. of electron in it are 18 Y must be A