Francium
Francium (), formerly known as eka-caesium and actinium K , is a chemical element that has the symbol Fr and atomic number 87. It has the lowest known electronegativity of all known elements, and is the second rarest naturally occurring element (after as more
Chemical warfare
Chemical warfare involves using the toxic properties of chemical substance s to kill, injure or incapacitate an enemy .
Chemical warfare is different from the use of conventional weapon s or nuclear weapon s because the destructive effects of chemical weapons are not primarily du more
Elias Ashmole
, c. 1681, below.
Elias Ashmole (23 May 1617 – 18 May 1692 ), the celebrated English antiquary , was a politician , officer of arms , student of astrology and alchemy , and an early speculative Freemason . He supported the royalist side during the English Civil War , and at the more
Speed of light :"Lightspeed" redirects here. For other uses, see Lightspeed (disambiguation) .
:For other uses of "speed of light", see speed of light (disambiguation)
The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or the Latin word celerit more
Enzyme
of the enzyme TIM , surrounded by the space-filling model of the protein. TIM is an extremely efficient enzyme involved in the process that converts sugar s to energy in the body.
Enzymes are protein s that catalyze (i.e. accelerate ) chemical reaction s. In enzymatic reactions, the molec more