Questions

Because the refractive index of glass is highest, light travels slowly in Glass. 

We know that the speed of light depends on the refraction index. The higher the index of refraction is, the slower the speed of light is.

R.I of air and vacuum = 0 (air is a teeny bit more but can be taken as 0)
R.I of water = 1.33
R.I of glass = 1.4.

Hence, Light travels slowest in Glass.

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.

Hence, the reactivity of an atom arises from the existence of unpaired electrons in the valence shell.

Tips

It would be wise to save this question for the interviewing manager, and not for a peer/technical discussion. Nobody likes a kiss-up, but letting management know that you will communicate openly and honestly with them, always scores big points. The last part of the question can be a good barometer about how easy it will be to become a top performer. You can follow up with a discussion of how you have been successful in your previous jobs.

Normally it takes about 22 days to become anorexic, but for some people it can be as little as 16 days or as many as 42 days.

Of course this depends a little bit on your starting weight/BMI and the health condition of the person.