How can an atom emit a photon of light?

Answer 1

Generally, this happens when an electron in an excited energy state drops to a lower energy state. Since energy cannot be destroyed, the difference in energy is emitted in the form of a photon.

Conversely, an atom can absorb a photon if it is of the right wavelength to knock an electron from a low energy state into a higher energy state.

Most phosphorescent pigments rely on this reversible process... when they lose their glow (emission of photons), you just hold it up to a bright light source to "recharge" the electrons (absorption of photons).

Answer 2

Electrons orbit the nucleus at certain levels (your quantum numbers). The bigger the orbit, the more energy the orbit possesses. When the orbit drops into a lower orbit, the orbit has less energy. The extra energy is emitted in the form of electromagnetic energy (a photon of light).

How did the electron get into a higher orbit in the first place? The atom absorbed energy from electromagnetic radiation (a photon of light) which forced the electron into a higher orbit (which is how the atom 'stores' the energy it absorbed).

Then again, if you're real clever, when the atom absorbs energy, you can capture the emitted energy instead of letting it escape via electromagnetic radiation. If you dope silicon with N-type material (phosphorous, for example) and mate it with silicon doped with P-type material (boron, for example), you can get the entire electron to jump from the N-type material to the P-type material instead dropping back into a lower orbit around it's original phosphorous atom. The electron can then be routed through your electrical circuit to create electrical energy from solar radiation.

If you're taking chemistry and have studied how many electrons can occupy each 'shell', you should be able to look at your periodic table and figure out why silicon doped with phosphorous and boron work so well for this.

Answer 3

When an electron returns to the ground state from its excited state, it must emit the excess energy and it does so as a photon of light.

Answer 4

The atom loses power. in many instances it somewhat is a results of an electron dropping to a decrease power state. PartB: an atom can emit mild especially wavelengths ruled via the style of atom, how lively the electron grew to become into, and the way many ranges it dropped. categories of atoms can emit photons in diverse, yet discreet, wavelengths. it somewhat is the source of 'emission traces' in spectroscopy. Scientists using this device can show you how to already know what variety (or types) of atoms emitted the mild, and what variety (or types) of atoms have been between the mild source and the observer. the 2nd little bit of information comes from absorption traces.

Answer 5

OTOH, wasn t it Newton who said that an object - a hydrogen atom in an excited state, in my example here - will continue in its existing condition or state unless acted upon by an external force.

Where s the cause that leads to the emission of a photon? Does the atom think ahead to its future state? Maybe this comment belongs in the philosophy group.

I think that this question is trickier than it seems.
N

Answer 6

When electrons return from an excited level to a lower energy level they emit EM radiation. It is a very specific wavelength depending on what element it is and which excited level it started in and which level it ended up in. This is the basis for emission and absorbtion spectroscopy as well as delayed phosphorescence.