Answer:
Lithium-7
Step-by-step explanation:
By carefully inspecting the diagram we can see three different sub-particles.
1) Electrons (-vely charged, outside the nucleus)
2) Protons (+vely charged, Inside nucleus)
3) Neutrons (uncharged, Inside nucleus)
Mass Number:
Mass number is the number of protons and neutrons present in the nucleus of an atom.
Therefore, in our problem there are 4 neutrons and 3 protons.
So, the mass number is 7.
Atomic Number:
Atomic number is the number of protons present in the nucleus. This number shows the identity of an atom. If you go through the periodic table you will find that the atomic number 3 is for Lithium.
Result:
Lithium-7