400
The STABLE, nonmetal, gases are put HERE (They are stable because their outer electron shell is FULL. They are NONreactive),
while the MOST reactive nonmetals are THERE (because their outer shell is ALMOST full and are never found uncombined in nature)
What is GROUP 18, the INERT or NOBLE Gases are STABLE and GROUP 17, the HALOGENS are HIGHLY REACTIVE