An element `M` has an atomic mass 19 and atomic number 9. Its ion is represented by

An element M has atomic mass 19 and atomic number 9 . Its ion is represented as

An element M has an atomic number 9 and atomic mass 19. Its ion will be represented by (1) M (2) M^(2+) (3) M^(-) (4) M^(2-)

An element M has an atomic number 9 and mass number 19. Its ion will be represented by (1) M (2) M^(2+) (3) M^(-) (4) M^(2-)

Atomic number of an element represents: