How many electron does a Florine ion (F-) have?
A. 19
B. 20
C. 21
D. 22

Florine ion (F-) has 10 electrons

Fluorine (symbol F) is one of the halogen elements in the form of gas, located in period 2, group 17 and including the p block.

Has atomic number 9, with the electron configuration:

1s² 2s² 2p5⁵

Fluorine to obtain stability according to the noble gas element (neon) will bind one electron to form a negative ion (anion) F-, so that the electron configuration becomes

1s² 2s² 2p⁶, so there are 10 electrons (is not in the answer option)