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.
These guys are behind one of the greatest software breakthroughs of all time. Believe it or not, there was a time when our computers were incapable of functioning like a calculator, a time before Microsoft Excel. Enter Dan Bricklin and Bob Frankston, two men who wanted to see their calculators come to life. By creating VisiCalc, the first electronic spreadsheet, that's exactly what they did. Bricklin and Frankston would work at night because computer time was cheaper at night. They thought of it as a visual calculator and that is why they gave it the name VisiCalc.