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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 ...
"alex trebek shows "Did you mean: who is alex trebek" in reference to Jeopardy!'s rule of answers being in the form of a question. [62] "assistant regional manager" shows "Did you mean: assistant to the regional manager", referencing The Office. [citation needed] "anagram" shows "Did you mean: nag a ram". [63]
Modern simultaneous CHNS combustion analyzer. Elemental analysis is a process where a sample of some material (e.g., soil, waste or drinking water, bodily fluids, minerals, chemical compounds) is analyzed for its elemental and sometimes isotopic composition.
Some elements emit weakly and others (Na) very strongly. Gold, silver, platinum, palladium, and a number of other elements do not produce a characteristic flame color, although some may produce sparks (as do metallic titanium and iron); salts of beryllium and gold reportedly deposit pure metal on cooling. [12] The test is highly subjective.
Elements in the same group tend to show similar chemical characteristics. Vertical, horizontal and diagonal trends characterize the periodic table. Metallic character increases going down a group and from right to left across a period. Nonmetallic character increases going from the bottom left of the periodic table to the top right.
Hence, in many cases the elements of a particular group have the same valency. However, this periodic trend is not always followed for heavier elements, especially for the f-block and the transition metals. These elements show variable valency as these elements have a d-orbital as the penultimate orbital and an s-orbital as the outermost orbital.
The indispensable element test is a standard for distinguishing preparation and attempt in a criminal case. [ 1 ] : 683 A person who does every act needed to commit a crime, except for one necessary or indispensable element, is not guilty of having made an attempt .
As a synthetic element, it is not found in nature and can only be made in a particle accelerator. It is radioactive; the most stable known isotope, 267 Rf, has a half-life of about 48 minutes. In the periodic table, it is a d-block element and the second of the fourth-row transition elements. It is in period 7 and is a group 4 element.