Select the appropriate options and complete the following paragraph.
(2, 7, 18, 32, atomic mass, atomic number, hydrogen, lithium)
In the modern periodic table, all known elements are listed in increasing order of their _____ . It start with the lightest elements . The modern periodic table has ______ group and ____ preiods . The first period contains only ____ elements while the seventh period contains ______ elements .

Explanation

atomic numbers, hydrogen, 18, 7, 2, 32