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.
Excel is a spreadsheet program in the Microsoft Office system. You can use Excel to create and format workbooks (a collection of spreadsheets) in order to analyze data and make more informed business decisions.ctivate and use an add-in. On the File tab, choose Options, and then choose the Add-Ins category. Near the bottom of the Excel Options dialog box, make sure that Excel Add-ins is selected in the Manage box, and then click Go.