The correct answer is option (B): Kr+
Explanation:
When a gaseous mixture of He, Ne, Ar, and Kr is irradiated with photons that have just enough energy to ionize argon (Ar), the following points are important:
Ionization energies (approximate values):
Since the photon energy is just enough to ionize Ar (15.8 eV), it cannot ionize He or Ne (which require more energy), but it can ionize Kr (which requires less).
Hence, only Kr will be ionized, forming Kr+.
Resonance in X$_2$Y can be represented as
The enthalpy of formation of X$_2$Y is 80 kJ mol$^{-1}$, and the magnitude of resonance energy of X$_2$Y is:
Such a group of atoms is called a molecule. Obviously, there must be some force that holds these constituent atoms together in the molecules. The attractive force which holds various constituents (atoms, ions, etc.) together in different chemical species is called a chemical bond.
There are 4 types of chemical bonds which are formed by atoms or molecules to yield compounds.