List of top Science Questions on Atomic Number and Mass Number

What is the effective atomic number (EAN) of [Cd(NH3)4]2+ ?
Explain with examples
(i) Atomic number,
(ii) Mass number,
(iii) Isotopes
(iv) Isobars.
Give any two uses of isotopes.
Composition of the nuclei of two atomic species X and Y are given as under 
 XY
Protons 66
Neutrons66

Give the mass numbers of X and Y. What is the relation between the two species?
Complete the following table.
Atomic NumberMass NumberNumber of NeutronsNumber of ProtonsNumber of ElectronsNumber of the Atomic Species

9

-

10

-

-

-

16

32

-

-

-

Sulphur

-

24

-

12

-

-

-

2

-

1

-

-

-

1

0

1

0

-