Periods \\\\(4\\\\) and \\\\(5\\\\) are called long periods as they contain \\\\(18\\\\) elements each. \\\\(4\\\\)th period is called the first long period and the inert gas in this period is \\\\(Kr\\\\).\\\\(5\\\\)th period is the second long period where \\\\(Xe\\\\) is the inert gas element.