To solve the problem, we need to identify the period to which the element with atomic number 17 belongs.
1. Understanding Periods in the Periodic Table:
The periods in the periodic table correspond to the number of electron shells (energy levels) in an atom. For example:
- Period 1: Elements with 1 electron shell (e.g., H, He)
- Period 2: Elements with 2 electron shells (e.g., Li, Be, B, C, N, O, F, Ne)
- Period 3: Elements with 3 electron shells (e.g., Na, Mg, Al, Si, P, S, Cl, Ar)
- Period 4: Elements with 4 electron shells, and so on.
2. Identifying the Element:
The element with atomic number 17 is chlorine (Cl), which is located in Period 3 of the periodic table. Chlorine has 3 electron shells.
Final Answer:
The element with atomic number 17 belongs to Period 3 (Option C).