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
The Cu Bird Cu bird is dressed, it flies to better lands, and the other birds blame the hoot owl. This is why the latter calls at night to the Cu bird, "Ticú-ticú", and why it cannot see during the day. There is a song titled "El pájaro cu" in the Mexican Son Jarocho style. According to one source, "pájaro cu" is a name used in the Yucatan Peninsula for the russet-crowned motmot, a colorful bird. The Cu Bird The Cu bird (Spanish: "pájaro cu" or "cú") is a bird from a Mexican folktale that is unhappy with its looks. According to the