A certain atom has 20 electrons, 21 neutrons, and 20 protons. What is the atomic mass of the atom?

Diffraction is when light is bent around obstructions. which of the these observation about clouds would indicate diffraction? a) after rain storms, you can sometimes see rainbows. b) clouds are white or gray and cannot be seen through. c) on a cloudy day, the temperature tends to be cooler than a sunny day. d) the edges of dark clouds appear lighter. this

If i add water to oil what will happen

Which suspect most likely committed the robbery and how do you know