How many protons, neutrons and electrons are present in a Lithium (Li+) ion?

On a periodic table, we can see that the atomic number for lithium is 3. The atomic number represents the number of protons in an atom, so Lithium has 3 protons. The atomic mass is the number of protons and neutrons of an element. As seen on a periodic table, Lithium has an atomic mass of 7. We know the proton number is 3, so 7-3 = 4, is our number of neutrons. Finally, as an atom is neutral in charge, the protons (positive charge) equal the number of electrons (negative charge). However, in this question we are being asked the electrons in a lithium ion. Lithium, as a metal, donates electrons and so must have lost an ion in order to have a +1 charge. Therefore, the number of electrons must be 2.