In atoms, protons and neutrons orbit the nucleus in one or more shells. Each shell has a specific limit on the number of protons or neutrons it can hold. When these shells are full, the resulting ...

When building an atom, pay close attention to the particles' electrical charges. Protons have a charge of +1. Electrons have a charge of -1. Neutrons are neutral, as its name implies. A stable atom ...

For four years, James Chadwick was a prisoner of war in Germany. When World War I ended, he returned to his native England to rejoin the mentor of his undergraduate days, Ernest Rutherford. Now head ...