4. (True or False) The electron structure of an atom is determined by diregt observation using X-rays.

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

What is the mass defect of a mole of nuclei with 1.8 x 10^15 j/mol binding energy?

Earth's axis of rotation is tilted at an angle of 23.5 degrees. what is one change you would see on earth if its axis was not tilted?