Some elements produce no visible color in the flame test yet all elements have electrons that can be put into an excited state why don't we see colors from those elements

When will le chatelier's principle come into effect? at the beginning of a reaction, when there are only reactants when a reaction has reached chemical equilibrium when a catalyst is added to a reaction mixture when a reaction is occurring but not yet at equilibrium

When you mate two plants together the terms is called? answer it fast as possible plz! i have a test tomorrow!

There is one girl i like and i don't know how to tell her that, i have a feeling she knows but if she doesn't i don't want to make a fool out of myself how is one way to boost my confidence on asking her out