Answer:
B
The chemical formula does not show how the atoms are connected to one another
Concept:
When an atom has incomplete number of electron in its outermost orbit then it has great tendency to react with another atom which satisfies their octate either by sharing or by transferring their electrons. The involved electrons are called valence electrons. These electrons will effect the energy level because of the transition of these electrons from one energy level to another energy level.
In case of electrovalent compound, the valance electron complete their octate by transferring their valence electrons while in the covalent compound, they complete their octate by the sharing of their valence electrons.
Hence, the valence electron of the atom effect the energy levels by the transition from one state to another state in the bond formation.
The nucleus of an atom of any element is located at the very center. It contains subatomic particles, proton and neutron. That's why it contains the greater mass, because only the electrons orbit the nucleus. So, you would expect the arrow to point somewhere in the center. A picture of nitrogen's nucleus is shown in the attached picture.
Add the reltive atomic mass of Ca and O which are 40 and 16 respectively after addition we get molecular mass of CaO which is 40+16=56 now divide atomic mass of O by molecular mass of CaO and multiply it with 100 as show n 16/56 *100=28.57%
