Answer and Explanation;
Structure; the nucleus has 3 protons and 4 neutrons, while the energy levels or the orbitals have 3 electrons. The identity atom is lithium atom (3 protons and three electrons) with an electron configuration of 1s^2 2s.
Charge; the atom has zero charge; it is neutral because the number of protons is equal to the number of electrons.
Its atomic number is 3; since atomic number is the number of protons in the nucleus of an atom (3 protons).
It has a mass number of 7; mass number is the sum of neutrons and protons in the nucleus of an atom ( 3 protons + 4 neutrons).
Atoms contain three sub-atomic particles called protons, neutrons and electrons. The protons and neutrons are found in the nucleus at the center of the atom. The nucleus is very much smaller than the atom as a whole. The electrons are arranged in shells around the nucleus.
In a neutral atom the number of electrons in an atom is always the same as the number of protons (protons = electrons).