Answer:
Number of shells
Explanation:
Across the period on the periodic table, the number of shells remains the same. There is no variation or trend for the number of shells on a period.
- The number of shell is the energy level corresponding to an atom.
- As we go from period to period, the energy level increases by 1.
- The period number corresponds to the number of shells.
- Elements in period 4 will have 4 shells.
- There is no variation of any sort in the number of shell across a period.
