Question

What do the following have in common? Ne-20, f-1, Mg+2

A)  They are isomers of each other.
B) 

They all have the same number of electrons.
C)  They are different elements so they have nothing in common.
D)  They are all located within the same region of the periodic table.

Answer 1

Answer is: B) They all have the same number of electrons.
1) ²⁰NeAtomic number of neon is 10, mass number is 20:
Neon have 10 protons, 10 electrons (atomic number) and 10 neutrons (mass number - atomic number).
2) F⁻¹
Fluorine have atomic number 9.
Fluorine have 9 protons (atomic number) and 10 electrons (9 +1).
3) Mg²⁺
Magnesium have atomic number 12.
Magnesium have 12 protons and 10 electrons (12-2).