Answer:
Alkenes, Markovnikov's, Alkenes, Alkyl halides, and less.
Explanation:
Alkenes must undergo addition because they have easily broken π bonds.
Markovnikov's rule states in the addition of HX to an unsymmetrical alkene, the H atom bonds to the less substituted carbon atom.
Alkenes are unsaturated hydrocarbons because they have fewer than the maximum number of hydrogen atoms per carbon.
Alkyl halides have good leaving groups and therefore readily undergo substitution and elimination reactions.
In hydroboration, the boron atom bonds to the less substituted carbon.
<u>Answer:</u> The energy of photon is 
<u>Explanation:</u>
The relation between energy and wavelength of light is given by Planck's equation, which is:

where,
E = energy of the light = ?
h = Planck's constant = 
c = speed of light = 
= wavelength of photon = 0.122 m
Putting values in above equation, we get:

Hence, the energy of photon is 
O valence electron number is the answer