Simplify the following text for a Grade 12 native English-speaking person.
Original: The number of valence electrons is also important for determining the group of an element in the Periodic table , because an element 's number of valence electron is the same as the number of its group in the periodic table .
Simplified: The number of valence electrons of an element is determined by its periodic table group ( vertical column ) in which the element is categorized .