Answer:
We identify an element from its atomic number = number of protons
So here the atomic number is 4 since it says 4 protons present.
The element is Berylllium, Be.
For a neutral atom atomic number = number of protons (positively charged) = number of electrons(negatively charged)
So the neutral atom contains 3 neutrons, 4 protons and 4 electrons.
Mass number = number of protons + neutrons
Since mass of an atom depends on the nucleus (protons and neutrons are present inside the nucleus)
Mass number = 3 + 4
Mass number=7.
The ion has 1+ charge which means the neutral atom has lost 1 negative electron.
So The answer is
Ion has 3 neutral neutrons
4 positive protons
3 negative electrons