Incompletely filled orbitals in representative elements are

The number of periods in the long form of the periodic table is

The amount of energy required to convert 3 moles of sodium atoms in the gaseous state to form sodium ions, if the ionisation enthalpy of Na is 5.1 ev/atom is

Among Mg, Mg²⁺, Al, Al³⁺ the largest and smallest species respectively are

Out of the following metals, the one which requires radiation of highest frequency to cause emission of electrons is

_________ is not a Dobereiner triad.

The effective nuclear charge of an atom depends upon

When a neutral atom is converted into cation, there is

The configuration associated with biggest jump between second and third ionisation energy is

The incorrect statement among the following is