During an energy exchange, a chemical system absorbs energy from its surroundings. What is the sign of ΔEsys for this process? Explain.
Solution: The spectrum of hydrogen atom has played a very important role in the development of atomic structure. It can be obtained by passing an electric discharge through the gas taken in the discharge tube under low pressure. The emitted light is analysed with the help of spectroscope. The spectrum consists of a large number of lines appearing in different regions of wavelengths. The line spectrum observed in case of hydrogen atom can be quantitatively explained using Bohr’s model. When an electron jumps from a lower orbit to a higher orbit, it absorbs energy. When the electron jumps from higher orbit to lower orbit, it emits energy. Step1: a) When electron jumps from n = 2(lower orbit) to n = 6(higher orbit) energy level, energy is absorbed. b) As we move from lower orbit to higher orbit, the distance between the nucleus and the orbit increases. As a result, the radii also increases. So, when an electron jumps from an orbit of radius 4.76 A (higher orbit) to one of radius 0.529 o A (lower orbit), energy is emitted. c) When electron jumps from n = 6(lower orbit) to n = 9(higher orbit) energy level, energy is absorbed. --------------------