Ytterbium is an element with the chemical symbol Yb and atomic number 70, which means it has 70 protons in its nucleus. It belongs to the lanthanide series, a group of elements in the periodic table known as rare earth metals. Ytterbium is a soft, silvery-white metal that is relatively stable in air and water. It is a good conductor of electricity and heat, and it has interesting magnetic properties.

Ytterbium has several practical applications in technology and science. It is used as a radiation source in portable X-ray machines, as a dopant in fiber optic amplifiers for telecommunications, and in atomic clocks that are accurate to within a few billionths of a second. Ytterbium also has potential uses in cancer therapy and quantum computing.