Scientists make hypothesis in order to make an educated guess on the outcome of the experiment.
The answer to 4 is A.
The answer to 5 is C.
The answer is never because there's no electricity
4p, 3d, 3p, 3s, 2p, 2s and 1s orbitals may be occupied during de-excitation.<span />
A control group is the group in an experiment that does not receive any sort of change, to then be compared to the other treated objects at the end of the study.
