organizes all discovered chemical elements in rows (called periods) and columns (called groups) according to increasing atomic number. Scientists use the periodic table to quickly refer to information ...

We know that matter is made up of particles called atoms and that an element ... structure of sodium can also be shown in a diagram. Each dot represents an electron. Since the atomic number ...

Photo: Niels Bohr's research notes for his new atomic theory Rutherford's find ... emitted by the radioactive element radium) at a sheet of gold foil only 1/3000 of an inch thick, and tracing ...

but also the atomic structure, including a precise determination of the ionization potential of this element which has no ...