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A period 4 element is one of the chemical elements in the fourth 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 ...
A mnemonic is a memory aid used to improve long-term memory and make the process of consolidation easier. Many chemistry aspects, rules, names of compounds, sequences of elements, their reactivity, etc., can be easily and efficiently memorized with the help of mnemonics.
118 chemical elements have been identified and named officially by IUPAC.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).
A recognisably modern form of the table was reached in 1945 with Glenn T. Seaborg's discovery that the actinides were in fact f-block rather than d-block elements. The periodic table and law are now a central and indispensable part of modern chemistry. The periodic table continues to evolve with the progress of science.
4 9 F 2 5 10 Ne 2 6 [Ne] 3s: 3p: 11 Na 1 - 12 Mg 2 - 13 Al 2 1 14 Si 2 2 15 P 2 3 16 S 2 4 17 Cl 2 5 18 Ar 2 6 [Ar] 4s: 3d: 4p: 19 K 1-- 20 Ca 2-- 21 Sc 2 1 - 22 Ti 2 2 - 23 V 2 3 - 24 Cr 1 5 - 25 Mn 2 5 - 26 Fe 2 6 - 27 Co 2 7 - 28 Ni 2 8 - 29 Cu 1 10 - 30 Zn 2 10 - 31 Ga 2 10 1 32 Ge 2 10 2 33 As 2 10 3 34 Se 2 10 4 35 Br 2 10 5 36 Kr 2 10 6 ...
Not all topics the periodic table shows are straightforward and undisputed. Some are chosen by looking at the scientific arguments presented in sources, which depend on chemistry and physics. Apart from science, also editorial choices are made. For example, it is quite common to show the "18-column" format (with two extra rows below the main ...
4: Each atom has four near neighbours, 2 at 275.4 pm, 2 at 285.4 pm. The next four at distances 326.3 pm and four more at 334.2 pm. [17] Strongly distorted hcp structure. α-Ga: A11: Orthorhombic: Cmce (No. 64) 8: each Ga atom has one nearest neighbour at 244 pm, 2 at 270 pm, 2 at 273 pm, 2 at 279 pm. [18] The structure is related to that of ...
Helium 2 He 4.0026: 2: Lithium 3 Li 6.94: Beryllium 4 Be 9.0122: Boron 5 B 10.81: Carbon 6 C 12.011: Nitrogen 7 N 14.007: Oxygen 8 O 15.999: Fluorine 9 F 18.998: Neon 10 Ne 20.180: 3: Sodium 11 Na 22.990: Magnesium 12 Mg 24.305: Aluminium 13 Al 26.982: Silicon 14 Si 28.085: Phosphorus 15 P 30.974: Sulfur 16 S 32.06: Chlor ...