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 ...

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) ...

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 ...

Mrs Roberts: What do you think you're made of? Mr Spellman: Big question. Grit, determination, hard-working, handsome, charming, funny. Mrs Roberts: Well, I guess. But you're actually made of atoms.

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 ...