گەرد: جیاوازیی نێوان پێداچوونەوەکان
ناوەڕۆکی سڕاو ناوەڕۆکی زیادکراو
Husen (لێدوان | بەشدارییەکان) پەڕەیەک دروست کرا بە '==گەرد== گەرد (Molecule) : بریتییە لە بچووکترین بەشی رووێک (Substance) کە تایبەتمەندی فیزیایی و کی...' |
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ھێڵی ٢:
گەرد (Molecule) : بریتییە لە بچووکترین بەشی رووێک (Substance) کە تایبەتمەندی فیزیایی و کیمییاییەکانی ئەو ڕووەی هەیە. پیکهاتووە لە دوو یان زیاتر ئەتۆم ([http://en.wikipedia.org/wiki/Atom Atoms]). گڕوپێک لە ئەتۆمی لێکچوو یان جیاواز یەکدەگرن بە هۆی بەستەری یان هێزی کیمیای (Chemical Bonds).
==Structure==
<!--Code included from the [[Periodic table (standard)]] article:-->
{{Periodic table}}
==Alternative versions==
Other [[alternative periodic tables]] exist.
Some versions of the table show a dark stair-step line along the metalloids. Metals are to the left of the line and non-metals to the right.<ref>[http://www.doe.virginia.gov/VDOE/Instruction/Science/ScienceCF-PS.doc Science Standards of Learning Curriculum Framework]</ref>
The layout of the periodic table demonstrates recurring ("periodic") chemical properties. Elements are listed in order of increasing [[atomic number]] (i.e., the number of [[proton]]s in the [[atomic nucleus]]). Rows are arranged so that elements with similar properties fall into the same columns (''groups'' or ''families''). According to [[quantum mechanics|quantum mechanical]] theories of [[electron]] configuration within atoms, each row (''period'') in the table corresponded to the filling of a quantum [[Electron shell|shell]] of electrons. There are progressively longer periods further down the table, grouping the elements into ''s-'', ''p-'', ''d-'' and ''f-blocks'' to reflect their [[electron configuration]].
In printed tables, each element is usually listed with its [[element symbol]] and [[atomic number]]; many versions of the table also list the element's [[atomic mass]] and other information, such as its abbreviated [[electron configuration]], [[electronegativity]] and most common [[valence number]]s.
As of 2011, the table contains 118 chemical elements whose discoveries have been confirmed. The first 94 are found naturally on Earth, and the rest are [[synthetic elements]] that have been produced artificially in [[particle accelerators]]. Elements 43 (technetium), 61 (promethium) and all elements greater than 83 (bismuth), beginning with 84 (polonium) have no stable isotopes. The atomic mass of each of these element's isotope having the longest [[half-life]] is typically reported on periodic tables with parentheses.<ref>[http://www.ptable.com/ Dynamic periodic table]</ref> Isotopes of elements 43, 61, 93 (neptunium) and 94 (plutonium), first discovered synthetically, have since been discovered in trace amounts on Earth as products of natural radioactive decay processes.
The primary determinant of an element's chemical properties is its [[electron configuration]], particularly the [[valence shell]] electrons. For instance, any atoms with four [[valence electrons]] occupying p orbitals will exhibit some similarity. The type of orbital in which the atom's outermost electrons reside determines the "block" to which it belongs. The number of [[valence shell]] electrons determines the family, or group, to which the element belongs.
<div style="float:right; margin:5px;">
{| class="wikitable" style="margin:auto;"
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| Subshell||S||G||F||D||P
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| style="background:#ddd;"| Period|| || || || ||
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| style="background:#ddd;"| 1 ||1s|| || || ||
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| style="background:#ddd;"| 2 ||2s|| || || ||2p
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| style="background:#ddd;"| 3 ||3s|| || || ||3p
|-
| style="background:#ddd;"| 4 ||4s|| || ||3d||4p
|-
| style="background:#ddd;"| 5 ||5s|| || ||4d ||5p
|-
| style="background:#ddd;"| 6 ||6s|| ||4f||5d||6p
|-
| style="background:#ddd;"| 7 ||7s|| ||5f||6d||7p
|-
| style="background:#ddd;"| 8 ||8s||5g||6f||7d||8p
|}</div>
The total number of [[electron shell]]s an atom has determines the period to which it belongs. Each shell is divided into different subshells, which as atomic number increases are filled in roughly this order (the [[Aufbau principle]]) (see table). Hence the structure of the table. Since the outermost electrons determine chemical properties, those with the same number of valence electrons are grouped together.
Progressing through a group from lightest element to heaviest element, the outer-shell electrons (those most readily accessible for participation in chemical reactions) are all in the same type of orbital, with a similar shape, but with increasingly higher energy and average distance from the nucleus. For instance, the outer-shell (or "[[Valence electron|valence]]") electrons of the first group, headed by [[hydrogen]], all have one electron in an s orbital. In hydrogen, that s orbital is in the lowest possible energy state of any atom, the first-shell orbital (and represented by hydrogen's position in the first period of the table). In [[francium]], the heaviest element of the group, the outer-shell electron is in the seventh-shell orbital, significantly further out on average from the nucleus than those electrons filling all the shells below it in energy. As another example, both carbon and lead have four electrons in their outer shell orbitals.
Note that as [[atomic number]] (i.e., charge on the [[atomic nucleus]]) increases, this leads to greater [[spin-orbit coupling]] between the nucleus and the electrons, reducing the validity of the quantum mechanical orbital approximation model, which considers each atomic orbital as a separate entity.
The elements [[ununtrium]], [[ununquadium]], [[ununpentium]], etc. are elements that have been discovered, but so far have not received a [[trivial name]] yet. There is a [[Systematic element name|system for naming them temporarily]].
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