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Double-ended nail – a rare type of nail with points on both ends and the "head" in the middle for joining boards together. See this patent. Similar to a dowel nail but with a head on the shank. Double-headed (duplex, formwork, shutter, scaffold) nail – used for temporary nailing; nails can easily pulled for later disassembly
A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
The form with the f-block included in the main body is sometimes called the 32-column [6] or long form; [33] the form with the f-block cut out the 18-column [6] or medium-long form. [33] The 32-column form has the advantage of showing all elements in their correct sequence, but it has the disadvantage of requiring more space. [ 34 ]
Iron is a chemical element; it has the symbol Fe (from Latin ferrum 'iron') and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's outer and inner core.
41 of the 118 known elements have names associated with, or specifically named for, places around the world or among astronomical objects. 32 of these have names tied to the places on Earth, and the other nine are named after to Solar System objects: helium for the Sun; tellurium for the Earth; selenium for the Moon; mercury (indirectly), uranium, neptunium and plutonium after their respective ...
Iron(II) chloride tetrahydrate, FeCl 2 ·4H 2 O. In chemistry, iron(II) refers to the element iron in its +2 oxidation state. The adjective ferrous or the prefix ferro-is often used to specify such compounds, as in ferrous chloride for iron(II) chloride (FeCl 2). The adjective ferric is used instead for iron(III) salts, containing the cation Fe 3+.
Sam Kean (2011), The Disappearing Spoon and Other True Tales of Madness, Love, and the History of the World From the Periodic Table of the Elements, Back Bay Books/Little Brown and Company; John Emsley (2011), Nature's Building Blocks: An A-Z Guide to the Elements — New Edition, Oxford University Press
The periodic table of the chemical elements.The columns represent the groups.Groups 1, 2 and 13 to 18 constitute the main group. Sometimes groups 3 and 12, as well as the lanthanides and actinides (the two rows at the bottom), are also included in the main group.