How many covalent bonds can a selenium atom make

What is the difference between a weak and strong base? only some of the molecules of a weak base dissociate to produce hydrogen ions when mixed with water, but all of the molecules of a strong base dissociate to produce hydrogen ions. strong bases result in the production of hydronium, while weak bases produce hydroxide ions. only some of the molecules of a weak base dissociate to produce hydroxide ions when mixed with water, but all of the molecules of a strong base dissociate to produce hydroxide ions. strong bases react with acids to produce water, but weak bases do not react at all.