Period 4 element be dangerous in large enough quantities due to its radioactivity. Nickel (Ni) is an element in period 4, between cobalt and copper. Nickel is rare in the Earth's crust, mainly due to the fact that it reacts with oxygen in the air, with most of the nickel on Earth coming from nickel iron meteorites. However, nickel is incredibly common in the Earth's core; along with iron it is one of the two main components. Nickel is an important component of stainless steel, and in many superalloys. Copper (Cu) is an element in period 4, between nickel and zinc. Copper is
CU-SeeMe CU-SeeMe CU-SeeMe (also written as CUseeMe or CUSeeMe depending on the source) is an Internet videoconferencing client. CU-SeeMe can make point to point video calls without a server or make multi-point calls through server software first called a "reflector" and later called a "conference server" or Multipoint Control Unit (MCU). Later commercial versions of CU-SeeMe could also make point-to-point or multi-point calls to other vendor's standards-based H.323 endpoints and servers. CU-SeeMe was originally written by Tim Dorcey of the Information Technology department at Cornell University. It was first developed for the Macintosh in 1992 and later for the Windows platform