Which part of the experiment is not touched by the independent variable or is the normal/comparison

How do i complete this electrolysis of water lab? i’m at home, so i don’t have the materials, and the lab didn’t properly work and was incomplete at school.

If two atoms are bonded to a central atom with no lone pairs,how will they be arranged

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?