A bus traveled 280 kilometers between two cities . It left the first city at 3:00 p. m. and arrived at the second city at 7:00 p. m. What was the average speed of the bus during the trip ?

☆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