The carbon atom and hydrogen atoms are close together. The electrons from each atom feels the attraction from the proton in the nucleus of the other atom. This attraction pulls the atoms together and ...

The stuff you scrape off burnt toast is made primarily of atoms of carbon. But what makes up a carbon atom—or any other atom? The first subatomic particle to be identified was the electron, in 1898.

The picture shows a close-up of one carbon atom. A hydrogen atom has one proton as the nucleus and one electron in the region outside the nucleus. The electron and proton are attracted to each other.

But what makes oxygen different from carbon? It is the number of protons in the nucleus of an atom that is the defining feature of the atom. It's what makes one element different from another.

With this, researchers produced artificial radioisotopes like technicium and carbon-14 used in medicine ... This new tool could probe the atom's nucleus and offered applications in medicine ...