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A period 5 element is one of the chemical elements in the fifth row (or period) of the periodic table of the chemical elements.The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behaviour fall ...
Rhodium is a hard, silvery, durable metal that has a high reflectance. Rhodium metal does not normally form an oxide, even when heated. [25] Oxygen is absorbed from the atmosphere only at the melting point of rhodium, but is released on solidification. [26] Rhodium has both a higher melting point and lower density than platinum.
Period 4 includes the biologically essential elements potassium and calcium, and is the first period in the d-block with the lighter transition metals. These include iron , the heaviest element forged in main-sequence stars and a principal component of the Earth, as well as other important metals such as cobalt , nickel , and copper .
Group 5 is the new IUPAC name for this group; the old style name was group VB in the old US system (CAS) or group VA in the European system (old IUPAC). Group 5 must not be confused with the group with the old-style group crossed names of either VA (US system, CAS) or VB (European system, old IUPAC); that group is now called the pnictogens or ...
Early modern period – The chronological limits of this period are open to debate. It emerges from the Late Middle Ages (c. 1500), demarcated by historians as beginning with the fall of Constantinople in 1453, in forms such as the Italian Renaissance in the West, the Ming dynasty in the East, and the rise of the Aztecs in the New World.
The BP scale is sometimes used for dates established by means other than radiocarbon dating, such as stratigraphy. [5] [6] This usage differs from the recommendation by van der Plicht & Hogg, [7] followed by the Quaternary Science Reviews, [8] [9] both of which requested that publications should use the unit "a" (for "annum", Latin for "year") and reserve the term "BP" for radiocarbon estimations.
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The definition of which elements belong to this group differs. The most common definition includes five elements: two of the fifth period (niobium and molybdenum) and three of the sixth period (tantalum, tungsten, and rhenium). They all share some properties, including a melting point above 2000 °C and high hardness at room temperature. They ...