Columbia Encyclopedia

Search results

500 results found

periodic table

(Encyclopedia)CE5 periodic table, chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley. In the periodic table the elements are arrange...

Elements (table)

(Encyclopedia)Elements 1 Parentheses indicate most stable isotope; brackets enclose lower and upper bounds of weight variation. ...

periodic law

(Encyclopedia)periodic law, statement of a periodic recurrence of chemical and physical properties of the elements when the elements are arranged in order of increasing atomic number. Such an arrangement in the for...

moscovium

(Encyclopedia)moscovium mŏskōˈvēəm [key], artificially produced radioactive chemical element; symbol Mc; at. no. 115; mass number of most stable isotope 288; m.p., b.p., sp. gr., and valence unknown. Situated ...

Mendeleev, Dmitri Ivanovich

(Encyclopedia)Mendeleev, Dmitri Ivanovich mĕndəlāˈəf, Rus. dəmēˈtrē ēväˈnəvĭch myĭndyĭlyāˈəf [key], 1834–1907, Russian chemist. He is famous for his formulation (1869) of the periodic law and t...

Signs of the Zodiac (table)

(Encyclopedia)Signs of the Zodiac

Richards, Theodore William

(Encyclopedia)Richards, Theodore William, 1868–1928, American chemist, b. Germantown, Pa., Ph.D. Harvard, 1888. Richards was a professor at Harvard from 1891 until his death in 1928. In 1914 he received the Nobel...

Rydberg, Johannes Robert

(Encyclopedia)Rydberg, Johannes Robert yo͞oˈhänəs rôˈbərt rüdˈbĕryə [key], 1854–1919, Swedish physicist. Rydberg was a professor at Lund from 1901 to 1919. He is best known for his grouping of the freq...

Newlands, John Alexander Reina

(Encyclopedia)Newlands, John Alexander Reina, 1838–98, British chemist. He studied at the Royal College of Chemistry in London and worked as an industrial chemist. Newlands prepared the first periodic table of el...

atomic number

(Encyclopedia)atomic number, often represented by the symbol Z, the number of protons in the nucleus of an atom, as well as the number of electrons in the neutral atom. Atoms with the same atomic number make up a c...