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-Cut! ¡Cu-Cut! ¡Cu-cut! was a Catalan illustrated satirical magazine, written in Catalan. Published in Barcelona between 1902 and 1912, it followed the political line marked by Francesc Cambó's Lliga Regionalista. ¡Cu-cut!, named after the cuckoo bird (), was first published on 2 January 1902 and, like El Be Negre magazine that would be published later, it steadfastly opposed Lerrouxism in Spain. Its director was Manuel Folch i Torres and most articles were written by Josep Morató i Grau, Eduard Coca i Vallmajor and Manuel Urgellès, among others such as Josep Abril i Virgili and Vicenç Caldés i Arús. The main illustrators