Answer:
second energy level
Step-by-step explanation:
Valence electrons are those electrons which are present in outer most orbital of the atom.
This can be easily found through the electronic configuration of atom.
Electronic configuration of F:
F₉ = 1s² 2s² 2p⁵
We can see that the valence electrons are present in second energy level of F atom.
There are seven valence electrons of fluorine.
It is called halogens.
Halogens are very reactive these elements can not be found free in nature. Their boiling points also increases down the group which changes their physical states. i.e fluorine is gas while iodine is solid.
Fluorine:
1. it is yellow in color.
2. it is flammable gas.
3. it is highly corrosive.
4. fluorine has pungent smell.
5. its reactions with all other elements are very vigorous except neon, oxygen, krypton and helium.