Sarah throws a ball to Billy, but it does not go far enough for him to catch it. What must Sarah apply to her next throw in order for it to reach Billy?

Well to my expert knowledge and my exquisite calculations i think the the negative ion # 412 is the key to sucess

☆ionisation energy increases across a period from na -> ar☆ionisation energy decreases down a group from li -> fr☆ionic radius decreases across a period from na -> cl☆ionic radius increases down a groupfrom f -> ii hope it clarifies your doubts