Hydrogen, nitrogen, fluorine, oxygen, iodine, chlorine and bromine.
As early as the Renaissance and Baroque Periods, composers have started to be freelance in music. Wolfgang Amadeus Mozart worked as a freelance composer and performer in Vienna. Joseph Haydn Haydn, also a composer, music teacher and musician made struggles as a freelancer he educated himself all throughout the process before he became well-known. Ludwig van Beethoven was also a freelance composer in Vienna.
