Question

Write the atomic number of the element present in the third period and seventeenth group of the periodic table.

Answer 1

Identify the Element

• Third period elements: Na, Mg, Al, Si, P, S, Cl, Ar.
• Group 17 elements (halogens): F, Cl, Br, I, At, Ts.
• Common element in both lists: Chlorine (Cl).

Atomic Number

Chlorine (Cl) has atomic number 17.

Final Answer

The atomic number of the element in the third period and seventeenth group is 17.