The noble gas having only two electrons in its valence shell is:

60 The number of protons in one atom of an element X is 8. What will be the number of electrons in its ion x^2-? 61 If the number of protons in one atom of an element Y is 20, then the number of electrons in its ion Y²⁺ will be: 63 A covalent molecule having a double bond between its atoms is: 64 The molecules having triple bond in them are: