What evidence did this experiment provide that electrons are negatively charged?

What is the force of attraction between the particles in a salt crystal

Calcium hydride (cah2) reacts with water to form hydrogen gas: cah2(s) + 2h2o(l) → ca(oh)2(aq) + 2h2(g) how many grams of cah2 are needed to generate 45.0 l of h2 gas at a pressure of 0.995 atm and a temperature of 32 °c?

Using the periodic table, complete the table to describe each atom. type in your answers.a ? b? c? d? e? f?