Question

Chemistry question. Are these statements true or false?

a) A hydrogen atom in the n=3 state can emit light at only 2 specific wavelengths.

b)A hydrogen atom in the n=2 state is at a lower energy than one in the n=1 state.

c) The energy of an emitted photon equals the energy difference of the two states involved in the emission.

Answer 1

a) and c) are true. b) is false

Explanation:

Here's the main reason:

When a hydrogen atom absorbs a quantum of energy, it promotes its electron into a higher energy state (meaning an orbit of greater radius to Bohr). There are only specific energy states (levels) possible, and we number them n=1, n=2, n=3 etc.

When this electron descends to a lower energy, the atom emits a photon of light. The Law of Conservation of Energy requires that the energy of the photon equal the difference in energy between the initial and final states. Hence (c) is true.

The electron can drop into any lower state, and if it is initially at n=3, there are only two states lower, and only two energy changes are possible. Hence (a) is true.

However, for an electron at n=2, there is a lower state (n=1), so (b) is false.