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.
Re: What are the main type of system software? System software is computer software designed to operate and control the computer hardware and provides an architecture for running application software. System software can be divided into two types, operating systems and software utilities.