Gold is a Block D, Group 11, Period 6 element. The electronic configuration is [Xe] 4f¹⁴² 5d¹⁰ 6s¹. In its elemental form gold's CAS number is 7440-57-5. The gold atom has a radius of 144.2.pm and it's Van der Waals radius is 166.pm. 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 used in coinage and is a standard for monetary systems. It is also extensively used for jewelry, dental work, and for plating. It is used for coating certain space satellites, as it is a good reflector of infrared and is inert. One area that has seen significant growth is the use of gold in electronics, particularly within telecommunications, information technology and safety critical applications. Similarly, within computers there are usually gold-plated edge connectors. Gold bonding wires are used extensively within semiconductor packages, gold thick film inks are applied in the fabrication of hybrid circuits and gold's excellent solder wetting properties are used to form a very thin protective layer on copper laminate printed circuit boards.