Activation energy is defined as the least amount of energy that is needed to be available in a chemical system with potential reactants in order to result a chemical reaction. Therefore, the correct answer would be the first option: the heat released in a reaction.
Shape
A gas is shapeless all other things being equal. It will, if put in a container, occupy every part of the container.
A liquid could also be thought of shapeless. If put in a container, it need not occupy the entire container. It will occupy as much as its calculated volume will permit it to occupy.
A solid will only occupy its original shape.
Volume
A gas will occupy whatever container it is put in within limits. You cannot put a 72 mols of gas in a mm^3 container without some amazing ability to apply a lot of pressure.
A liquid will occupy a volume determined by its density and mass. In general liquids cannot be compressed.
Whatever volume a solid has to start with, it will retain that volume all other things being equal.
This is actually very hard to describe.
Answer:
n l m
����������������������������������
1 0 0 1s 1 2 2
����������������������������������
2 0 0 2s 1 2
2 1 1,0,-1 2p 3 6 8
����������������������������������
3 0 0 3s 1 2
3 1 1,0,-1 3p 3 6
3 2 2,1,0,-1,-2 3d 5 10 18
����������������������������������
4 0 0 4s 1 2
4 1 1,0,-1 4p 3 6
4 2 2,1,0,-1,-2 4d 5 10
4 3 3,2,1,0,-1,-2,-3 4f 7 14 32
Explanation: