All the following are signs of a chemical reaction, except

a. a change in color or odor.
b. a release of gas.
c. a change of state.
d. a change in energy.

What are the first two quantum numbers for the electrons located in subshell 4d? what are the first three quantum numbers for the electrons located in subshell 2s? how many electrons can be held in a sublevel l = 3? how many electrons can be held in the energy level n = 4? how many electrons in an atom can share the quantum numbers n = 4 and l = 3?