The energies, E, for the first few states of an unknown element are shown here in arbitrary units. n 1 2 3 4 ... E -42 -18 -8 -6 0A gaseous sample of this element is bombarded by photons of various energies (in these same units). Match each photon to the result of its absorption (or lack thereof) by an n=1 electron. Photon Energy Result OPTIONSA 42 n=1 to n=2B 34 n=1 to n=3C 31 n=1 to n=4D 24 electron ejected

Vander waals forces are inter molecular bonds that exist within molecules of the same substance. a water molecule is made up of oxygen and hydrogen atoms which share electrons between each other. the vander waals forces are forces that exist between multitude of different  molecules of water. dipole dipole forces is the type of vander waals force that exist in water. the oxygen atom which is more electronegative pulls the shared electron closer to itself thus generating a partial negative charge while the hydrogen acquire a partial positive charge. these two different charges causes attraction to occur in water molecules.

Ibelieve the answer is balance! hope my answer has you : )