Why is gain energy as they return to lower energy levels wrong

Which type of orbits are found in the principal energy level n = 2 a - s b - s, f c - s, d d - s, p e - s, p, d

If maltose undergoes hydrolysis what subunits does it results to?

Which statement is true regarding the diagram of circle p? the sum of y and z must be 2x. the sum of y and z must be x. the difference of z and y must be 2x. the difference of z and y must be x