Category
page 1Periods (periodic table)
period
row in the periodic table: repetition of properties in chemical elements when ordered by atomic number:
period 1
first row (or period) of the periodic table of the chemical elements
period 2
any of the chemical elements in the second row of the periodic table
period 3
third row of the periodic table
period 4
fourth row in the periodic table of chemical elements
period 6
row 6 of the periodic table
period 5
fifth row of the periodic table
period 7
any element in row 7 of the periodic table
period 8
period 8 (row 8) of the periodic table. (Today, theoretically only)
period 9
period 9 (row 9) of the periodic table (today, theoretical only)
period 10
row 10 of the periodic table (today, theoretical only)