An atomic model of aluminium displays the arrangement and number of subatomic particles within the atom. The centre of the atom is the nucleus containing the positively charged protons and neutral atoms of the atom. Orbiting the atom is a cloud of negatively charged electrons. The atomic number of an element equals the number of protons in the nucleus of an atom of that element. The atomic mass is the average sum of protons and neutrons in a sample of the element. In a neutrally charged atom, the number of electrons equals the number of protons.
Identify the number of protons, neutrons, and electrons in an atom of aluminium. The atomic number of aluminium is 13, indicating that the aluminium atom has 13 protons. The atomic mass of the stable isotope of aluminium is 27. The number of neutrons can then be determined by subtracting the number of protons from the atomic number to get a difference of 14 neutrons (27 -- 13 = 14). The number of electrons in a neutrally charged aluminium atom equals the number of protons, so the number of electrons is 13.
Paint 14 half-inch styrofoam balls yellow to represent the neutrons. Paint 13 half-inch styrofoam balls red to represent the protons. Paint 13 quarter-inch styrofoam balls black to represent electrons.
Create the nucleus of the atom by gluing the yellow and red styrofoam balls together into a large group.
Thread two black styrofoam balls onto a strand of floral wire. Thread eight black styrofoam balls onto a second strand of floral wire. Thread the remaining three black styrofoam balls onto a third strand of floral wire.
Arrange the floral wire with the styrofoam balls into three concentric circles around the nucleus. The innermost circle should have two model electrons, the middle circle should have eight model electrons, and the outermost circle should have three model electrons.
Secure the rings of electrons in place around the nucleus using additional strands of floral wire. This can be accomplished by cutting the floral wire to appropriate lengths and then twisting one end of the floral wire around the ring of electrons and inserting the other end into the styrofoam balls of the nucleus.