Which is more reactive, rubidium or hydrogen?

The element that has the greatest electronegativity is

Avolleyball player hit a ball with a mass of 0.25 kg. the average acceleration of the ball is 15.5 m/s². how much force did the volleyball player apply to the ball? 62.0 n 3.87 n 62.0 m/s² 3.87 m/s²

What volume of 0.500 mol/l hydrochloric acid, hci (aq) is required to react completely with 1.00 g of aluminum hydroxide, ai(oh)3 (s)?