What is matter made up of?
Matter is made up of atoms. All of the atoms known to humans are listed in the periodic table of elements.
Perhaps a better question is "what is matter?" Matter is anything that has mass and volume. Because matter has mass and volume, a property of all matter is density. If you take the matter's mass and divide it by the volume, you get the matter's density. Density is one of several physical properties of matter. Another physical property of matter is solubility. Malleability and ductility are two more. Malleability is matter's ability to be pounded into thin sheets. Ductility is how well the matter can be pulled into wires. Still another physical property of matter is thermal conductivity. That property refers to how well the matter conducts heat and temperature changes.
Matter also has chemical properties. Those will describe matter's ability to change into something else with new and different physical properties. Two common chemical properties of matter are flammability and reactivity.
Matter is anything that has mass or takes up space. Practically anything you observe is matter, except energy, such as thermal energy, light energy, and solar energy. Forms of energy have no mass so therefore are not forms of matter. Matter of made up atoms and these atoms can be any element that is found on the Periodic Table of Elements. Matter can be any combination of elements.