Ignoring, for the moment, electron spin and electron-electron interaction, suppose that one electron in a helium atom is in the ground hydrogen-like state (0,0,0) and the other is in an excited state (un, l, (i) explain why w(r1, r2) = w0,0,0(r1)& n,1,mų (r2) is not a suitable wave function to describe the helium atom in this state. (ii) explain how this problem is overcome? (b) assume now that spin and electron-electron interaction are taken into account. all states of the atom can be classified as singlet states or triplet states. answer the following questions: (i) give a brief explanation of what distinguishes a singlet state from a triplet state. (ii) the singlet and triplet states of the same electron configuration have different energies. explain why. (iii) draw a schematic diagram showing the states for a helium atom for an electron configuration 1s2p, taking account of electron-electron interaction, exchange energy and spin-orbit coupling effects. spacings do not need to be to scale, but you should label the levels with relevant quantum numbers and spectroscopic notation. (iv) for the ground state electron configuration 1s”, explain why there is a singlet state only.

Need asap ! what is the relationship between atmospheric pressure and the density of gas particles in an area of increasing pressure? (2 points) as air pressure in an area increases, the density of the gas particles in that area decreases. as air pressure in an area increases, the density of the gas particles in that area increases. as air pressure in an area increases, the density of the gas particles in that area remains constant. as air pressure in an area increases, the density of the gas particles in that area increases and decreases in an alternating pattern. 3. which of the following correctly describes a way in which earth's atmosphere interacts with the geosphere? (2 points) it contains gases that living organisms breathe. it contains gases that trap incoming solar radiation. it provides a medium for cycles that provide nutrients to living organisms. it provides a medium for water to move between earth's surface and the air. 4. which of the following is considered a drawback to using wind energy as a source of power? (2 points) wind energy is nonrenewable. wind energy produces large amounts of air pollution. 5. a meteorologist predicts that the weather in a region will soon change from clear skies to probable thunderstorms. prior to making this prediction, what did the meteorologist most likely observe on a barometer? (2 points) the barometer fell slightly. the barometer fell substantially. the barometer rose slightly. the barometer rose substantially. 6. which of the following do meteorologists not typically use weather balloons to record? (2 points) atmospheric pressure cloud types humidity temperature 7. during which step in the can crush lab did water vapor force air from the can? (2 points) the can was filled nearly to the top with water. the can was placed on the hot stove top burner for several minutes. the can was removed from the hot stove top burner. the can was placed upside-down in the water-filled pan.

Diamond will scratch quartz. true or false

Identify the theory that can be used to explain each phenomenon. answers diffraction: wave theory interference: wave theory reflection: both particle and wave theories refraction: both particle and wave theories