Question

Select the appropriate options and complete the following paragraph.
(2, 7, 8, 32, atomic mass, atomic number, hydrogen, lithium)
In the modern periodic table, all known elements are listed in increasing order of their
.. It starts with the lightest element_ and proceeds to the heavier elements. The
modern periodic table has groups and _ periods. The first period contains
only__ elements while the seventh periods contains elements.
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Answer 1

Answer:

In morden periodic table, all known elements are listed in increasing order of their atomic number..It starts with the lightest element hydrogen and proceeds to the heavier elements. The morden periodic table has 18 groups and 7 periods.The first period contains only 2 elements while seventh period contain 32 elements.