# What are Atoms Made of

Though atoms are the building blocks of all matter, there are only three types of particles of which they are composed. The combinations of these particles determine the physical and chemical properties of atoms. The three varieties of particles are protons, neutrons, and electrons.

The first particle is the proton. Its mass is between that of an electron and a neutron, being much closer to the neutron’s mass than the mass of the electron. The proton is contained within the nucleus, or center of the atom, and has a positive charge. The number of protons in an element is equal to the atomic number of that element.

The second component is the neutron. Having slightly more mass than the proton, the neutron is also bound to the nucleus of the atom. Differing from the proton, the neutron has no charge, or a neutral charge. Since the proton has a positive charge and the neutron has a neutral charge, the nucleus of the atom has a positive charge. Unlike protons and electrons, the number of neutrons in atoms of the same element may vary. These different versions of the same element are called isotopes.

The third particle is the electron. This particle is by far the smallest. You can use this analogy to understand the size of an electron: a proton is to an electron as a baseball is to a fly. Despite its small size, the electron has a charge equal to that of a proton. However, the charge of an electron is negative rather than positive.The number of electrons in an atom is always equal to the number of protons. Hence, the number of electrons can also be determined by the atomic number of the element. Since the electron has an equal and opposite charge, the atom has a neutral charge. The electron orbits the nucleus at incredibly fast speeds. An example is the hydrogen electron which travels about 2,200 kilometers per second. The electron is also extremely far away from the nucleus. Here is another example you can use to understand the distance between the nucleus and the electron: if the nucleus were the size of baseball and placed in the center of a football field, the fly (electron) would be in the lights. Since electrons are the outer shell of atoms, they determine the properties of the element, both physical and chemical.

Atoms are the smallest quantities into which an element can be divided. The pieces that make up these atoms are protons, neutrons, and electrons. Through different combinations of these particles, we are given the incredibly diverse range of elements we have today.