What Period would this element be in?

Period 2

Explanation:

From the picture provided, I am guessing this is Fluorine. Normal Fluorine has 9 protons, electrons, and atomic number. Thus, it can be found in the second period.

***Period # = # of electron shells

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.