How many valence electron do hydrogen have

Which statement correctly describes metallic bonds? a. they form when certain atoms lose electrons and other atoms gain electrons. b. they involve an attraction between anions and cations. they always involvpoth a metal and a nonmetal. d. they can only form between atoms of the same element. e. they form because electrons can move freely between atoms.

Reduction is a reaction which results in a in electrons and a in positive charge of the atom or ion 1) a- loss 1) b- gain 2) a-increase 2) b-decrease

What is a number added in front of a formula in order to balance the equation