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 number is a mathematical object used to count, measure, and label. The original examples are the natural numbers 1, 2, 3, and so forth. A notational symbol that represents a number is called a numeral. In addition to their use in counting and measuring, numerals are often used for labels (as with telephone numbers), for ordering (as with serial numbers), and for codes (as with ISBNs).