Témbongkeun sumber pikeun Logam alkali

{| align="right" style="margin:0 0 1em 1em;"
! [[Golongan tabél periodik|Golongan]]
! 1
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! [[Periode tabél periodik|Periode]]
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! [[Unsur periode 1|1]]
| {{element cell| 1|Hidrogén|H| |Gas|Nonlogam|Primordial}}
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! [[Unsur periode 2|2]]
| {{element cell| 3|Litium|Li| |Padet|Logam alkali|Primordial}}
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! [[Unsur periode 3|3]]
| {{element cell|11|Natrium|Na| |Padet|Logam alkali|Primordial}}
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! [[Unsur periode 4|4]]
| {{element cell|19|Kalium|K| |Padet|Logam alkali|Primordial}}
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! [[Unsur periode 5|5]]
| {{element cell|37|Rubidium|Rb| |Padet|Logam alkali|Primordial}}
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! [[Unsur periode 6|6]]
| {{element cell|55|Césium|Cs| |Padet|Logam alkali|Primordial}}
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! [[Unsur periode 7|7]]
| {{element cell|87|Fransium|Fr| |Padet|Logam alkali|Radio alami}}
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'''Logam alkali''' hartina [[dérét kimia|dérét]] [[unsur kimia|unsur]] nu kaasup [[Golongan tabél periodik|Golongan 1]] (cara [[International Union of Pure and Applied Chemistry|IUPAC]]) dina [[tabél periodik]]: [[litium]] ('''Li'''), [[natrium]] ('''Na'''), [[kalium]] ('''K'''), [[rubidium]] ('''Rb'''), [[césium]] ('''Cs'''), jeung [[fransium]] ('''Fr''') (tengetkeun yén [[hidrogén]], najan kaasup Golongan 1, jarang pisan némbongkeun paripolah nu sarupa jeung logam-logam alkali). Logam alkali téh hiji conto rimbagan pasipatan dina tabél periodik, anu ti luhur nepi ka handap watekna homolog.

== Ciri ==
[[Gambar:Alkalimetalle.jpg|thumb|350px|Logam alkali, dikeueum dina minyak mineral.]]
Logam alkali kagolongkeun unsur réaktif, nu matak di alam jarang kapanggih dina bentuk dasarna. Pikeun kaperluan di laboratorium, ieu bahan dikeueum dina [[minyak mineral]]. Najan kaasup logam, ieu unsur hipu bisa dikeureut, sabab dénsitasna kurang. Kalium jeung rubidium kaasup radioaktif lemah (teu matak bahya), sabab durasi isotop radioaktifna panjang.<!--

The alkali metals are silver-colored (cesium has a golden tinge), soft, low-[[density]] [[metal]]s, which react readily with [[halogen]]s to form [[ionic salt]]s, and with [[water (molecule)|water]] to form strongly [[alkali]]ne [[Base (chemistry)|(basic)]] [[hydroxide]]s. These elements all have one [[electron]] in their outermost shell, so the energetically preferred state of achieving a filled [[electron shell]] is to lose one electron to form a singly [[electric charge|charged]] positive [[ion]], or cation.

[[Hydrogen]], with a solitary electron, is usually placed at the top of Group 1 of the periodic table, but it is not considered an alkali metal; rather it exists naturally as a diatomic [[gas]]. Removal of its single electron requires considerably more energy than removal of the outer electron for the alkali metals.  As in the [[halogen]]s, only one additional electron is required to fill in the outermost shell of the hydrogen atom, so hydrogen can in some circumstances behave like a halogen, forming the negative [[hydride]] ion. [[Binary compound]]s of hydride with the alkali metals and some [[transition metal]]s have been prepared. Under extremely high [[pressure]], such as is found at the core of [[Jupiter]], hydrogen does become metallic and behaves like an alkali metal; see [[metallic hydrogen]].

Alkali metals have the lowest ionization potentials in their respective periods, as removing the single electron from the outermost shell gives them the stable inert gas configuration. But their second ionization potentials are very high, as removing an electron from a species having a noble gas configuration is very difficult.

Alkali metals are famous for their vigorous reactions with water, and these reactions become increasingly violent as one moves down the group.  The reaction with water is as follows:

Alkali metal + water → Alkali metal hydroxide + hydrogen gas

With [[potassium]] as an example:

:2K (s) + 2H<sub>2</sub>O (l) → 2KOH (aq) + H<sub>2</sub> (g)
-->
=== Réaksina dina amonia ===
Logam alkali dina [[amonia]] cair ngahasilkeun leyuran bulao nu [[paramagnétik]]. Mun geus ngadeukeutan jenuh, warnana jadi bungur, laju jadi métalik.

:[[Kalium|K]] + [[Amonia|NH<sub>3</sub>]] → K<sup>+</sup> + [[éléktron|e<sup>-</sup>]]

ku sabab leyuranana ngandung éléktron bébas, volumna jadi nambahan leuwih ti jumlah volum logam jeung amoniana. Ayana éléktron ogé ngajadikeun ieu leyuran alus salaku [[réduktor]] jeung [[konduktor (listrik)|konduktor listrik]]. Ieu leyuran henteu stabil, sabab biasana robah jadi [[amida]]. Ieu réaksi, mun digancangkeun ku ayana [[katalis]] (biasana [[beusi (III) nitrat]]), dipaké pikeun ngahasilkeun [[amida natrium]]:

:2 [[Natrium|Na]] + 2 [[Amonia|NH<sub>3</sub>]] → 2 [[Amisa natrium|NaNH<sub>2</sub>]] + [[Hidrogén|H<sub>2</sub>]]

Amidana bisa diékstrak atawa dirobah jadi [[azida natrium]] ku cara ngabulukbukkeun [[oksida nitrogén]] kana leyuran amonia:

:2 [[amida natrium|NaNH<sub>2</sub>]] + [[oksida natrium|N<sub>2</sub>O]] → [[azida natrium|NaN<sub>3</sub>]] + [[natrium hidroksida|NaOH]] + [[amonia|NH<sub>3</sub>]]

== Kacondongan ==
Logam-logam alkali mibanda sababaraha pola mun dipapay ti luhur ka handap - misalna waé éléktronégativitas nurun, réaktivitas naék, sarta nurunna titik lééh jeung golak. Dénsitasna biasana ngaronjat, iwal kalium nu hampang batan natrium.

<table border=0 cellpadding=2 cellspacing=0 width="100%">
 <tr>
  <td bgcolor="#CCCCFF">'''Logam alkali'''</td>
  <td bgcolor="#CCCCFF" align="center">'''Beurat Atom Baku ([[unit massa atom|u]])'''</td>
  <td bgcolor="#CCCCFF" align="center">'''Titik Lééh ([[kelvin|K]])'''</td>
  <td bgcolor="#CCCCFF" align="center">'''Titik Golak ([[kelvin|K]])'''</td>
  <td bgcolor="#CCCCFF" align="center">'''Dénsitas ([[gram|g]]·[[séntiméter|cm]]<sup>−3</sup>)'''</td>
  <td bgcolor="#CCCCFF" align="center">'''Éléktronégativitas ([[skala Pauling|Pauling]])'''</td>
 </tr>

 <tr>
  <td>Lithium</td>
  <td align="center">6.941</td>
  <td align="center">453.69</td>
  <td align="center">1615</td>
  <td align="center">0.534</td>
  <td align="center">0.98</td>
 </tr>
 <tr>
  <td bgcolor="#EEEEEE">Natrium</td>
  <td bgcolor="#EEEEEE" align="center">22.990</td>
  <td bgcolor="#EEEEEE" align="center">370.87</td>
  <td bgcolor="#EEEEEE" align="center">1156</td>
  <td bgcolor="#EEEEEE" align="center">0.968</td>
  <td bgcolor="#EEEEEE" align="center">0.93</td>
 </tr>
 <tr>
  <td>Kalium</td>
  <td align="center">39.098</td>
  <td align="center">336.53</td>
  <td align="center">1032</td>
  <td align="center">0.89</td>
  <td align="center">0.82</td>
 </tr>
 <tr>
  <td bgcolor="#EEEEEE">Rubidium</td>
  <td bgcolor="#EEEEEE" align="center">85.468</td>
  <td bgcolor="#EEEEEE" align="center">312.46</td>
  <td bgcolor="#EEEEEE" align="center">961</td>
  <td bgcolor="#EEEEEE" align="center">1.532</td>
  <td bgcolor="#EEEEEE" align="center">0.82</td>
 </tr>
 <tr>
  <td>Césium</td>
  <td align="center">132.905</td>
  <td align="center">301.59</td>
  <td align="center">944</td>
  <td align="center">1.93</td>
  <td align="center">0.79</td>
 </tr>
 <tr>
  <td bgcolor="#EEEEEE">Fransium</td>
  <td bgcolor="#EEEEEE" align="center">(223)</td>
  <td bgcolor="#EEEEEE" align="center">? 295</td>
  <td bgcolor="#EEEEEE" align="center">? 950</td>
  <td bgcolor="#EEEEEE" align="center">? 1.87</td>
  <td bgcolor="#EEEEEE" align="center">0.7</td>
 </tr>
</table>
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==Biological occurrences==

* The metal lithium is not essential for any biological functions, but was found to exist in extremely tiny quantities in [[umbilical cord]] blood.  This was found during a study by taking blood samples of newborns from both the umbilical cord and the mother at the time of birth, and subjecting the samples to a number of tests.  They found that there was 7 times the amount of lithium in blood than previously believed. (Krachler and Rossipal 488)  While it is considered a non-essential trace element (an element needed in extremely tiny amounts for proper growth), lithium also has medicinal uses.  A double-blind, placebo-controlled, two-week long study conducted by a group of doctors on severely depressed patients proved that lithium is a key component in the treatment of severe depression. (Joffe, Levitt, and Sokolov, 791)  It has also been proven to play a role in the treatment of other mental disorders. (Bildik et al. 277)  One recorded instance was the case of a girl who developed a condition known as [[Neuroleptic malignant syndrome]], who was given an antipsychotic drug (a tranquilizing drug that induces a state of relative calm).  She quickly developed the symptoms of NMS, and was quickly hospitalized.  There, doctors began treating her for the disorder, and in the final stage of her treatment, lithium was administered to her to help stabilize her mental functions.  Weeks later, she was released and was in good physical health, but retained her previous diagnosis of Bipolar Disorder (a mental disorder that encompasses periods of mania and depression interspersed by periods of normal behavior). (Bildik et al. 278)
* Sodium and potassium are very common alkali metals.  These elements are essential for the existence of all known life.  They are found in the cytoplasm (organic fluid, mainly water) of all living cells, and they are critical to everyday cell operation and regulation. (Chang and Tsong 587)  Also, a common sodium salt, sodium chloride (table salt), has been identified many times as a contributor to [[hypertension]] in humans. (Sharp 727) A double-blind, two-month study was conducted on a group of elderly adults by modestly cutting their salt intake, to find if cutting salt intake would lower blood pressure.  Some in the group were given half the salt that others were given for the duration of the study.  The findings indicated that those who were given only half the amount of salt experienced a drop in blood pressure of up to 7.2 mm Hg (millimeters Mercury). (Cappacio and Markandu 850)        
* Rubidium is not required for any known biological functions, but is known to be an unnecessary and toxic trace-element in humans. (Krachler and Rossipal 488)  A recent study conducted on rubidium levels in freshwater ecosystems from Lake Erie and two Arctic lakes indicate that this element biomagnifies (the concentration grows as you move higher in the food chain) in marine food chains.  This was found by collecting samples of fish, birds and plankton, and conducting tests on them.  They found that the predatory animals (the small-mouth bass, for example) had higher rubidium concentrations than animals commonly considered to be prey. (Campbell et al. 1163)  
* Caesium (also spelled cesium) is not typically found in any biological systems.  However, cesium salt (cesium chloride) is a popular medicinal supplement taken to counteract the effects of damaged or diseased cells on the body. (Ackerman et al. 1011)  Furthermore, this supplement has been shown to be toxic to human physiology, and has caused very serious side effects in people, and potentially can be deadly if not taken carefully. (Ackerman et al. 1011)
* Francium is an extremely rare element, and its chemical and physical properties have not been characterized to the same extent as the other alkali metals.  It is known to have the same chemistry as cesium and is primarily an exotic curiosity in the world of physics.  At any one moment in time, less than one ounce of francium is believed to exist on Earth, and its most stable [[isotope]] has a half life of a little less than 23 minutes.("Physics update" 9)  This makes working with the element dangerous and difficult and radiochemistry techniques must be used to characterize its chemical properties.  It has not been found to exist in any biological systems, and while there is no direct evidence of this, it is assumed to be true due to the rarity and instability of the element.
-->

== Rujukan ==
* [[:en:Alkali metal|Alkali metal]], ti Wikipédia basa Inggris (19 Péb. 2008)

== Tumbu kaluar ==
* [http://www.scienceaid.co.uk/chemistry/periodictable/alkalimetals.html Science aid:Alkali metals] {{Webarchive|url=https://web.archive.org/web/20080203151311/http://www.scienceaid.co.uk/chemistry/periodictable/alkalimetals.html |date=2008-02-03 }} A simple look at alkali metals
* [https://web.archive.org/web/20060925151836/http://www.wpbschoolhouse.btinternet.co.uk/page03/Alkali_Metals.htm Doc Brown, Alkali metals]
* [http://www.chemguide.co.uk/inorganic/group1/properties.html Atomic and Physical Properties of the Group 1 Elements] An in-depth look at alkali metals

{|style="text-align: center;" border="1" cellpadding="2" 
|+ '''Pedaran potongan tabél periodik di luhur:'''
| bgcolor="{{element color/Logam alkali}}" | Logam alkali
| Nomer atom nu <font color="{{element color/Solid}}">hideung</font> hartina padet
| style="border:{{element frame/Primordial}};" |Wates garis pinuh nunjukkeun [[unsur primordial]] (leuwih kolot batan [[Marcapada]])
| style="border:{{element frame/Natural radio}};" | Wates garis pegat-pegat nunjukkeun [[peluruhan radioaktif|unsur radioaktif]] alami nu isotopna teu leuwih kolot batan Marcapada
|}

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{{LogamAlkali}} 
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[[Kategori:Logam alkali]]
[[Kategori:Tabél periodik]]
[[Kategori :logam]]