Question

students choose an option
#7
periods tell what about an element?
periodic table groups and families
please deck interactive slide
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your response
the number of energy levels around an atom
of an element
the mass of an element
the number of electrons

Explanation:

In the periodic table, periods (rows) indicate the number of energy levels (electron shells) around an atom. For example, hydrogen (H) in period 1 has 1 energy level, sodium (Na) in period 3 has 3 energy levels.

Answer:

the number of energy levels around an atom