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
Naming of chemical elements after Amerigo Vespucci The non-transuranic element samarium is named after Vasili Samarsky-Bykhovets, and gadolinium is indirectly named (via the mineral gadolinite), after Johan Gadolin. Lecoq de Boisbaudran, who named the element gallium after his native land of France (from Latin "Gallia" meaning Gaul) denied that the element's naming was for a pun on his own name ("le coq" means "the rooster" in French, as does "gallus" in Latin). Some chemical elements are named after places on the planet earth. Five are named after currently existing countries – polonium (named after Poland), francium and gallium (named after France), nihonium (named after