I know the answer is “b. the existence of unpaired electrons in the valence shell” ,but I need an explanation as to why or how… can anyone help me?
When atoms react they do so in order to reach the lowest energy, which is the most stable. The electrons orbitals will overlap in the way that reduces the energy the most. Orbitals of similar energy will produce the greatest stabilisation.The answer you gave isn’t the whole story, it depends what species is reacting with what. The effective nuclear charge on the atom will affect the energy of the valance electrons. So basically, if the species reaction have valance electrons of similar energy they will be able to produce a large decrease in energy/stabilisation, so are more reactive.
the existence of unpaired electrons in the valence shell. .