Elements
- 181
- WebElements: Holmium
- Extensive information on history, uses, occurrence, compounds, and properties.
- 182
- Wikipedia: Holmium
- Properties of the element, including its history, applications, and characteristics.
- 185
- Hydrogen Energies and Spectrum
- The Bohr model for an electron transition in hydrogen between quantized energy levels with different quantum numbers n yields a photon by emission with quantum energy.
- 187
- Wikipedia: Hydrogen
- Properties of the element, including its history, applications, and characteristics.
- 190
- USGS Minerals Information: Indium
- Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
- 191
- WebElements: Indium
- Extensive information on history, uses, occurrence, compounds, and properties.
- 192
- Wikipedia: Indium
- Properties of the element, including its history, applications, and characteristics.
- 195
- USGS Minerals Information: Iodine
- Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
- 196
- WebElements: Iodine
- Extensive information on history, uses, occurrence, compounds, and properties.