The principle which states that no two electrons in the same orbitals of an atom have same value for all four quantum numbers is the

How much of 5g of radioactive element whose half life is 50days remains after 200days?

The group VIII elements are the inert gases because they 

Na\(_2\)X  ⇌  2Na\(^+\)  +  X\(^{2-}\)

The bond between Na and X is likely to be

The highest isotope of hydrogen is