The atomic number of calcium is 20 which means it has 20 protons and as an atom (not an ion) it also has 20 electrons. These are in four energy levels (1 though 4) .
Your answer would be D.
Answer:
H2O2
Explanation:
There's hydrogen and ox in the formula to represent
1/6 + 1/8 = 7/24
24
≅ 0.2916667
