If you are eligible for reinstatement and wish to return to federal service the reinstatement program affords you an advantage other applicants don't have. You will have to locate openings and at a grade at or below the grade you left federal service. The process is straight forward and outlined below.
The period number is an identifier used to describe the row of the standard periodic table in which the element appears. The lanthanoids and actinoids are extensions of Periods 6 and 7 respectively, hence their assignment to those Periods.
A decimal number, or just decimal, refers to any number written in decimal notation, although it is more commonly used to refer to numbers that have a fractional part separated from the integer part with a decimal separator (e.g. 11.25).