- What are "valence electrons", and why do they make an atom "reactive"?

Discover Questions

I'll tried to figure this out but can't seem to get it. If someone could please help.? Find the perimeter of a circular sector with a radius of 5 meters and an area of 17 square meters.? Find the energy of the photon required to excite a hydrogen atom from the n=1 state to the n=5 state.? Prove that x³+3x+14>0 for x>-2.? Is a photon an electromagnetic wave and how does it compare to a gravity wave?