Fluorine has 7 valence electrons. Valence electrons are the electrons in the outermost shell of an atom, and they play a crucial role in chemical bonding and reactions.
Fluorine is located in Group 17 (also known as Group VIIA) of the periodic table, which is the halogen group. Elements in this group have 7 valence electrons. This is because the outermost electron shell of these elements can hold a maximum of 8 electrons, and they are just one electron short of achieving a stable, full outer shell.
In the case of fluorine, its electron configuration is 1s2 2s2 2p5. The outermost shell (the second shell) contains 7 electrons: 2 in the 2s orbital and 5 in the 2p orbital. This makes fluorine highly reactive, as it tends to gain one electron to achieve a stable octet configuration, forming a fluoride ion (F–).