According to the periodic table, which of these elements has the most electron energy levels? A. fluorine (F) B. sodium (Na) C. calcium (Ca) D. rubidium (Rb)

17

Explanation:

The number of elementary particles in the atom X = 52

The mass number of atom X = 35

The information required = The atomic number

The number elementary particles of the atom = The number of protons + The number of neutrons + The number of electrons

The mass number of an atom = The number of protons + The number of neutrons

∴ The number of electrons = The number elementary particles of the atom - The number elementary particles of the atom

The number of electrons = 52 - 35 = 17

In a neutral atom, the number of protons = The number of electrons = 17

The atomic number of atom, X = The number of protons in X = 17