This element is classified as a lanthanide and it is the most abundant of the rare-earth elements of the earth’s crust. It is the most reactive of the rare-earth metals and is used as a catalyst to refine petroleum.
This is a non-metal and the most abundant element in the Universe. It is the basic fuel for nuclear reactions in the stars. It is a gaseous substance on Earth and the lightest element in the Universe.
This element is a noble gas which is gas at room temperature. It is characterized by its brilliant green and orange spectral lines. This noble gas is used in fluorescent light bulbs, luminous signs, high-speed photography.