Question

Because a given element's atoms emit only certain photons of light, only certain _______ are occurring in those particular atoms.

Short answer

Because a given element's atoms emit only certain photons of light, only certain energy transitions are occurring in those particular atoms.

Step-by-step solution

Identifying the related phenomenon to emitted photons from an atom

Recall that an atom emits photons when electrons transition between different energy levels. These transitions cause the characteristic spectra for each element. The blank must be filled with a term related to this phenomenon, which is only allowing specific photons to be emitted.

Filling the blank

Based on the explanation in Step 1, the term we need to fill in the blank is "energy transitions." Therefore, the completed sentence is: Because a given element's atoms emit only certain photons of light, only certain energy transitions are occurring in those particular atoms.

Key concepts

Photon Emission

When an electron in an atom moves from a higher energy level to a lower energy level, a photon is emitted. This happens because the electron loses energy, and this energy is released as light.
The energy of the emitted photon corresponds specifically to the difference in energy between the two levels. This unique energy difference ensures that each photon has a distinct wavelength or color.
In simple terms, photon emission is like a staircase. Electrons 'drop' from a step that is high to a step that is lower, and in doing so, they give off light that can be seen or measured, depending on the spacing between steps:

• High step to low step = photon emitted
• Energy difference = photon energy

Each element has its unique set of energy levels, which is why each one produces its own set of emitted photons.

Atomic Spectra

The unique fingerprint of each element's emitted photons is called its atomic spectra. These spectra are the patterns of light emitted by the atoms of an element due to photon emission.
When these emitted photons are passed through a prism or a diffraction grating, they separate into a series of lines. These lines make up the atomic spectrum, which can either be an emission or absorption spectrum depending on what is being studied.
Imagine the atomic spectrum as a barcode. Each element has a unique pattern of lines based on its own electron energy transitions

• Emission spectrum: Bright lines on a dark background
• Absorption spectrum: Dark lines on a colorful background

These spectra are incredibly useful for identifying elements in stars, distant galaxies, and other substances, as each element's "barcode" is recognizable.

Electron Energy Levels

Electrons in an atom occupy specific regions called energy levels or electron shells. These levels are sometimes visualized as concentric circles around the nucleus, though in reality they are more complex.
These levels are fixed, meaning electrons can only be in one level or another and nowhere in-between. This quantization gives rise to the concept known as "quantum theory."
Electrons typically fill the lowest energy levels first, staying close to the nucleus. However, they can jump to higher levels if they gain energy, and they fall back down to lower levels by releasing energy, often in the form of photon emission.
Think of energy levels like floors in a building where:

• The lowest floor is the ground state.
• Higher floors are excited states.
• Moving to a higher floor requires energy intake.
• Coming down releases energy, often as light.

Understanding these levels is crucial for grasping how atoms emit light and thus create atomic spectra.