Fluorine is located in Group 17 of the periodic table, which is also known as the halogen group. As for the number of valence electrons, fluorine has seven valence electrons.
The reason for this is that fluorine has an atomic number of 9, which means it has 9 electrons total. These electrons are arranged in energy levels around the nucleus. The first energy level can hold a maximum of 2 electrons, and the second level can hold up to 8 electrons. For fluorine, the distribution of its electrons is 2 in the first level and 7 in the second level. The electrons in the outermost shell (the second shell) are called valence electrons, and since fluorine has 7 in that shell, it has seven valence electrons. This configuration is what makes fluorine very reactive and eager to bond with other elements to achieve a full outer shell of 8 electrons.