According to kinetic theory the gas molecules are in a state of constant rapid motion in all possible directions colloiding in a random manner with one another and with the walls of the container and between two successive collisions molecules travel in a straight line path but show haphazard motion due to collisions.
The answer should be “Three electrons are lost, creating Al+3”. Al‘s electron configuration is 1s2 2s2 2p6 3s2 3p1, and by losing 3 electrons its second shell becomes the full outer one.
I think how it burns is not a physical property since that involves a chemical change while all of the other properties involve the physical structure or a physical change. I hope this helps.