What are “Table Scan’s” and “Index Scan’s”?

These are ways by which SQL Server searches a record or data in table. In “Table Scan” SQL Server loops through all the records to get to the destination. For instance if you have 1, 2, 5, 23, 63 and 95. If you want to search for 23 it will go through 1, 2 and 5 to reach it. Worst if it wants to search 95 it will loop through all the records.
While for “Index Scan’s” it uses the “B-TREE” fundamental to get to a record. For “BTREE” refer previous questions.