Which element would release the most energy while adding an electron to a neutral atom in the gas phase?

If a solution is considered basic, then a) the hydroxide ion and hydronium ion concentrations are equal. b) the hydroxide ion concentration is less than the hydronium ion concentration. c) the hydronium ion concentration is greater than the hydroxide ion concentration. d) the hydroxide ion concentration is greater than the hydronium ion concentration.

Consider the elements bromine and chlorine; which elements has a larger ionic radius ?

Match the mixture with the substance// i really need on this guys (it’s a pic btw)