For example, the atomic number of sodium is 11. Every sodium atom has 11 protons and 11 electrons. It has 11 positive charges and 11 negative charges. Atoms of different elements usually have ...

__1803: __English chemist-physicist John Dalton starts using symbols to represent the atoms of different elements. Dalton, considered the father of modern atomic theory, made a logbook entry that day ...

One hundred fifty years after Russian chemist Dmitri Mendeleev published his system for neatly arranging the elements, the periodic table it gave birth to hangs in every chemistry classroom in the ...

If P(nl; r) is the (nl) radial wave function in an atom of atomic number N, and PH(nl; r) is the corresponding wave function of hydrogen, then, for a given configuration and for large N N-1/2P(nl; r) ...

THE first Friday evening discourse of the new session at the Royal Institution was delivered on November 2 by Dr. F. W. Aston, who took as his subject “Elements and Isotopes”. That a chemical element ...

A Game of the Elements, published Genius Games. In Periodic: A Game of the Elements, players collect sets of elements and advance their research by moving through the periodic table.