The periodicity in the periodic table is caused by the configuration of electrons in the atomic structure. This creates a pattern in the properties of elements. Among the given options, Electrons is the correct answer.
The periodicity in the periodic table is caused by the configuration of electrons in the atomic structure. As elements progress across the periodic table, electrons add to the outer energy levels. After the energy level is full, the following element starts a new energy level. This repetition in electron configuration creates a pattern or 'periodicity' in the physical and chemical properties of elements. So, among the given options, Option 2: Electrons is the correct answer.
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