Atoms are the building blocks of matter.
Each atom of an element is neutral. Being neutral means there is no net charge.
Atoms have equal numbers of protons and electrons. The positively charged protons are found in the nuclei of atoms, and the negatively charged electrons are outside the nuclei.
An atom’s atomic number equal to the atom’s number of protons and electrons
Aluminum’s atomic number is 13, thus each aluminum atom has 13 +(protons) and 13- (electrons).
How to make models of atoms can be found in “Janice VanCleave’s books of “Super Science Models.”