Flame Test Lab Notes

Introduction to Electromagnetic Radiation

Electromagnetic radiation includes visible light, ultraviolet radiation, X-rays, and other types originating in atoms.
- Originates from the movement of electrons between energy levels in an atom.

Ground State: Electrons occupy the lowest energy levels, close to the nucleus, before absorbing energy.
Excited State: When electrons absorb energy (from heat, electricity, or light), they jump to higher energy levels.
- The excited state is temporary; electrons will fall back to ground state due to the attraction of protons in the nucleus.

Upon returning to ground state, energy is released as photons of electromagnetic radiation.
Energy Gap: The difference in energy between ground state and excited state.
- The energy released during this transition can be in forms like visible light, ultraviolet radiation, infrared radiation, heat, or X-rays.

Different forms of electromagnetic radiation are defined by their energy levels:
- X-rays: Highest energy
- Ultraviolet: High energy, can break chemical bonds and damage cells.
- Visible Light: Intermediate energy; consists of colors in the rainbow (red to violet).
- Infrared: Lowest energy of the mentioned types.

Energy levels in an atom are quantized like rungs on a ladder.
- Each electron jump corresponds to the emission of a photon.
- The type of emitted energy depends on how far the electron falls.
Example of jumps:
- Small jump = low energy (infrared radiation)
- Large jump = high energy (ultraviolet radiation or X-ray).
The gaps between energy levels vary across different elements.

Electrons can emit different colors of light based on the distance of their fall back to ground state.
- Colors of the Rainbow: Red, orange, yellow, green, blue, indigo, violet have varying energy levels.
  - Red = lowest energy, violet = highest energy.
- The transition from a higher to lower energy level results in the emission of light corresponding to the energy difference.
Atoms can emit different colors simultaneously, creating a unique "fingerprint" for each atom.

Spectroscopy enables scientists to analyze light emitted from elements.
Example: The element helium was first discovered in the sun (1868) through its light wavelength before being found on Earth (1885).
The same methods apply to identify elements in unknown chemical compounds during experiments.