Ascientist uses an accelerator and high energy electrons to study the particles inside the protons of a helium atom. what particles is the scientist studying?

Which statement about hf is true? it is zero for any compound in its standard state. it is positive when the bonds of the product store more energy than those of the reactants. it is negative when a compound forms from elements in their standard states. it is zero for any element that is in the liquid state.

Need what is special about water as a compound? how does water regulate climate? what drives water evaporation?   why is the water vapor fresh water when it rises from the ocean? why might freshwater in the form of snow take longer to enter the water cycle again than liquid precipitation?   what is an aquifer? what role do people play in the water cycle? plz just answer as many as you can ! thx if you !

The bohr model of the atom explained why emission spectra are discrete. it could also be used to explain the photoelectric effect. which is a correct explanation of the photoelectric effect according to the model?