There are 18 groups (columns) in the periodic table. Group 1 (also known as the alkali metals) is the column on the far left of the table. Elements in the same group have similar, but not identical characteristics. This is because they all have the same number of electrons in their outermost shell.
Software. Sometimes abbreviated as SW and S/W, software is a collection of instructions that enable the user to interact with a computer, its hardware, or perform tasks.
Definition of:system software. Software used to control the computer and develop and run applications. It includes programs such as operating systems, database managers, compilers, Web servers, router operating systems and control programs for other network devices. Contrast with application program.