Ultrasound wave assisted adsorption of congo red using gold-magnetic nanocomposite loaded on activated carbon: Optimization of process parameters.

See more Gold products. Gold (atomic symbol: Au, atomic number: 79) is a Block D, Group 11, Period 6 element with an atomic weight of 196.966569. The number of electrons in each of Gold's shells is 2, 8, 18, 32, 18, 1 and its electron configuration is [Xe]4f¹⁴² 5d¹⁰ 6s¹. The gold atom has a radius of 144 pm and a Van der Waals radius of 217 pm. Gold was first discovered by Early Man prior to 6000 B.C. In its elemental form, gold has a metallic yellow appearance. Gold is a soft metal and is usually alloyed to give it more strength. It is a good conductor of heat and electricity, and is unaffected by air and most reagents. It is one of the least reactive chemical elements. Gold is often found as a free element and with silver as a gold-silver alloy. Less commonly, it is found in minerals as gold compounds, usually with tellurium.

See more Carbon products. Carbon (atomic symbol: C, atomic number: 6) is a Block P, Group 14, Period 2 element. The number of electrons in each of Carbon's shells is 2, 4 and its electron configuration is [He]2s² 2p². In its elemental form, carbon can take various physical forms (known as allotropes) based on the type of bonds between carbon atoms; the most well known allotropes are diamond, graphite, amorphous carbon, glassy carbon, and nanostructured forms such as carbon nanotubes, fullerenes, and nanofibers . Carbon is at the same time one of the softest (as graphite) and hardest (as diamond) materials found in nature. It is the 15th most abundant element in the Earth's crust, and the fourth most abundant element (by mass) in the universe after hydrogen, helium, and oxygen. Carbon was discovered by the Egyptians and Sumerians circa 3750 BC. It was first recognized as an element by Antoine Lavoisier in 1789.