Classification ...

The correct order of negative electron gain enthalpy is:

In $$Cr$$, $$21^{st}$$ electron will enter in which orbital?

For the process,
$$X(g)+{ e }^{ - }\longrightarrow { X }^{ - }(g)\quad \quad \quad  \triangle H=x$$
$${ X }^{ - }(g)\longrightarrow X(g)+{ e }^{ - }\quad \quad \quad  \triangle H=y$$

The process requiring the absorption of energy is:

$$M_{(g)}+e^- \rightarrow M^{-}_{(g)}$$ ; $$\Delta H=-354\ kJ/mole $$ at $$300\ K$$, then the electron affinity value at $$0\ K$$ is:

Which of the following atoms should have the highest $$1^{st}$$ electron affinity?

Identify the least stable among the following:

Which pair of elements has the same characteristic chemical properties?

In which pair do both atoms have one electron only in an "s" orbital in their ground states?

The electron affinities of B,C, N and O are in the order of  _____________.