Lewis Acid-Base Concept. The Lewis theory classifies a substance as an acid if it acts as an electron-pair acceptor and as a base if it acts as an electron-pair donor. Other ways of classifying substances as acids or bases are the Arrhenius concept and the Bronsted-Lowry concept.ewis Acid-Base Concept. The Lewis theory classifies a substance as an acid if it acts as an electron-pair acceptor and as a base if it acts as an electron-pair donor. Other ways of classifying substances as acids or bases are the Arrhenius concept and the Bronsted-Lowry concept.
Microsoft Excel was created by Microsoft Corporation. It was first released in 1985.
Microsoft Excel was based on another program, the first spreadsheet, known as Visicalc. It was invented by two men called Bob Frankston and Dan Bricklin in 1978 and launched in 1979. There were a number of other spreadsheet programs around before Excel too, including one called Multiplan that Microsoft had created. Multiplan was launched in 1982 and Excel in 1985. The Microsoft Corporation was founded by Bill Gates.