The electron dot structure, also known as the Lewis dot structure, represents the valence electrons of an atom. Chlorine has an atomic number of 17, which means it has 17 electrons in total. However, when considering the valence electrons for drawing the electron dot structure, we only focus on the outermost shell.
Chlorine is in group 17 of the periodic table, which means it has 7 valence electrons. Therefore, the electron dot structure for chlorine includes 7 dots.