| Group | 1 |
|---|---|
| Period | |
| 1 | 1 H |
| 2 | 3 Li |
| 3 | 11 Na |
| 4 | 19 K |
| 5 | 37 Rb |
| 6 | 55 Cs |
| 7 | 87 Fr |
The alkali metals are a series of elements comprising Group 1 (IUPAC style) of the periodic table: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in In the Periodic table of the elements, a period is a horizontal row of the table A period 1 element is one of the Chemical elements in the first row (or period) of the periodic table of the chemical elements. Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 A period 2 element is one of the Chemical elements in the second row (or period) of the periodic table of the chemical elements. Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 A period 3 element is one of the Chemical elements in the third row (or period) of the periodic table of the elements. Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 A period 4 element is one of the Chemical elements in the fourth row (or period) of the periodic table of the elements. Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 A period 5 element is one of the Chemical elements in the fifth row (or period) of the periodic table of the elements. Rubidium (ruːˈbɪdiəm /rəˈbɪdiəm/ is a Chemical element with the symbol Rb and Atomic number 37 A period 6 element is one of the Chemical elements in the sixth row (or period) of the periodic table of the elements, including the Lanthanides Caesium or cesium (ˈsiːziəm is the Chemical element with the symbol Cs and Atomic number 55 A period 7 element is one of the Chemical elements in the seventh row (or period) of the periodic table of the elements. Francium (ˈfrænsiəm formerly known as eka-caesium and actinium K, is a Chemical element that has the symbol Fr and In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in A chemical element is a type of Atom that is distinguished by its Atomic number; that is by the number of Protons in its nucleus. In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in The International Union of Pure and Applied Chemistry ( IUPAC) (aɪjuːpæk or ay-yoo-pec) is an international Non-governmental organization The periodic table of the chemical elements is a tabular method of displaying the Chemical elements Although precursors to this table exist its invention is Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 Rubidium (ruːˈbɪdiəm /rəˈbɪdiəm/ is a Chemical element with the symbol Rb and Atomic number 37 Caesium or cesium (ˈsiːziəm is the Chemical element with the symbol Cs and Atomic number 55 Francium (ˈfrænsiəm formerly known as eka-caesium and actinium K, is a Chemical element that has the symbol Fr and (Hydrogen, although nominally also a member of Group 1, very rarely exhibits behavior comparable to the alkali metals). Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 The alkali metals provide one of the best examples of group trends in properties in the periodic table, with well characterized homologous behavior down the group.
The alkali metals are all highly reactive and are rarely found in elemental form in nature. As a result, in the laboratory they are stored under mineral oil. Mineral oil or liquid Petroleum is a By-product in the Distillation of Petroleum to produce Gasoline and other petroleum They also tarnish easily and have low melting points and densities. Potassium and rubidium possess a weak radioactive characteristic (harmless) due to the presence of long duration radioactive isotopes.
The alkali metals are silver-colored (caesium has a golden tinge), soft, low-density metals, which react readily with halogens to form ionic salts, and with water to form strongly alkaline (basic) hydroxides. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across Abundance Owing to their high Reactivity, the halogens are found in the environment only in compounds or as Ions Halide ions and oxoanions In Chemistry, an ionic compound is a Chemical compound in which Ions are held together in a lattice structure by Ionic bonds Usually the positively Water ( H2[[oxygen O]] H OH) is the most abundant Molecule on Earth 's surface composing of about 70% of the Earth's surface as In Chemistry, an alkali (from Arabic: Al-Qaly القلي القالي) is a basic, ionic salt of an Alkali metal In Chemistry, a base is most commonly thought of as an aqueous substance that can accept Protons This refers to the Brønsted-Lowry theory of acids and In Chemistry, hydroxide is the most common name for the diatomic Anion OH− consisting of Oxygen and Hydrogen 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 charged positive ion, or cation. The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J An electron shell may be crudely thought of as an Orbit followed by Electrons around an Atom nucleus. Electric charge is a fundamental conserved property of some Subatomic particles which determines their Electromagnetic interaction. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge
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. Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 This page is about the physical properties of gas as a state of matter Removal of its single electron requires considerably more energy than removal of the outer electron for the alkali metals. As in the halogens, 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. Abundance Owing to their high Reactivity, the halogens are found in the environment only in compounds or as Ions Halide ions and oxoanions Hydride is the name given to the negative Ion of Hydrogen, H− Binary compounds of hydride with the alkali metals and some transition metals have been prepared. A binary compound is a compound that contains two different elements such as NaCl (salt or Sodium chloride) In Chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings It commonly refers to any element in 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. Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface Metallic hydrogen results when Hydrogen is sufficiently Compressed and undergoes a phase change it is an example of Degenerate matter.
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. 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) + 2H2O (l) → 2KOH (aq) + H2 (g)
Contents |
Reaction in ammonia
Alkali metals dissolve in liquid ammonia to give blue solutions that are paramagnetic. Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Paramagnetism is a form of magnetism which occurs only in the presence of an externally applied magnetic field As the solution approaches saturation, it becomes deep purple, then metallic.
Because the solution contains free electrons, it occupies more space than the sum of the volumes of the metal and ammonia. Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J The presence of free electrons also makes these solutions very good reducing agents and good electrical conductors. A reducing agent (also called a reductant or reducer) is the element or a compound in a Redox (reduction-oxidation reaction (see Electrochemistry In Science and engineering, a conductor is a material which contains movable Electric charges. Since they are easier to handle than the metals themselves they are sometimes used as substitutes.
The solution is not stable over long periods, and the dissolved alkali metal will react to form the corresponding amide. In Chemistry, an amide is one of three kinds of Compounds (sometimes called acid amide the organic Functional group characterized This reaction, when accelerated with a catalyst (usually iron(III) nitrate), is used for the production of sodium amide:
The amide can be extracted, or it can be converted to sodium azide by bubbling nitrous oxide through the ammonia solution:
Trends
The alkali metals show a number of trends when moving down the group - for instance, decreasing electronegativity, increasing reactivity, and decreasing melting and boiling point. Iron(III nitrate, or ferric nitrate, is the Chemical compound with the formula Fe(NO33· 9H2O. Sodium amide, commonly called sodamide is the Chemical compound with the formula NaNH2 Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Sodium amide, commonly called sodamide is the Chemical compound with the formula NaNH2 Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 Sodium azide is the Chemical compound with the formula NaN3 This colourless Azide salt is a common reagent in Organic Nitrous oxide, commonly known as " laughing gas," is a Chemical compound with the Chemical formula N 2 O. Sodium amide, commonly called sodamide is the Chemical compound with the formula NaNH2 Nitrous oxide, commonly known as " laughing gas," is a Chemical compound with the Chemical formula N 2 O. Sodium azide is the Chemical compound with the formula NaN3 This colourless Azide salt is a common reagent in Organic Sodium hydroxide ( Na[[hydroxide OH]]) also known as Lye, caustic soda and (incorrectly according to IUPAC nomenclature Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Density generally increases, with the notable exception of potassium being less dense than sodium, and the possible exception of francium being less dense than caesium.
| Alkali metal | Standard Atomic Weight (u) | Melting Point (K) | Boiling Point (K) | Density (g·cm−3) | Electronegativity (Pauling) |
| Lithium | 6. The unified atomic mass unit ( u) or Dalton ( Da) or sometimes universal mass unit, is an unit of Mass used to express The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic For other uses of the words gram or gramme see Gram (disambiguation. A centimetre ( American spelling: centimeter, symbol cm) is a unit of Length in the Metric system, equal to one hundredth " Electronegativity " is the opposite of " Electropositivity," which describes an element's ability to donate electrons 941 | 453. 69 | 1615 | 0. 534 | 0. 98 |
| Sodium | 22. 990 | 370. 87 | 1156 | 0. 968 | 0. 93 |
| Potassium | 39. 098 | 336. 53 | 1032 | 0. 89 | 0. 82 |
| Rubidium | 85. 468 | 312. 46 | 961 | 1. 532 | 0. 82 |
| Caesium | 132. 905 | 301. 59 | 944 | 1. 93 | 0. 79 |
| Francium | (223) | ? 295 | ? 950 | ? 1. 87 | 0. 7 |
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. In placental Mammals the umbilical cord (also called the birth cord or funiculus umbilicalis) is the connecting cord from the developing Embryo 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). Neuroleptic malignant syndrome (NMS is a life-threatening neurological disorder most often caused by an adverse reaction to neuroleptic or antipsychotic drugs. 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. Hypertension, also referred to as high blood pressure, HTN or HPN, is a medical condition in which the Blood pressure is chronically elevated (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, caesium salt (caesium 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 caesium 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. Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides ("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.
Reference material
- Campbell, Linda M. , Aaron T. Fisk, Xianowa Wang, Gunter Kock, and Derek C. Muir (2005). "Evidence for Biomagnification of Rubidium in Freshwater and Marine Food Webs". Canadian Journal of Fisheries and Aquatic Sciences 62: 1161-1167.
- Chang, Cheng-Hung, and Tian Y. Tsong (2005). "Stochastic Resonance of Na, K-Ion Pumps on the Red Cell Membrane", Noise and Fluctuations: 18th International Conference on Noise and Fluctuations. American Institute of Physics.
- Sokolov, Stephen T. , Russell T. Joffe, and Anthony J. Levitt (2006). "Lithium and Triiodothyronine Augmentation of Antidepressants". Canadian Journal of Psychiatry 51: 791-793.
- Bauer, Brent A. , Robert Houlihan, Michael J. Ackerman, Katya Johnson, and Himeshkumar Vyas (2006). "Acquired Long QT Syndrome Secondary to Cesium Chloride Supplement". The Journal of Alternative and Complementary Medicine 12: 1011-1014.
- Erermis, Serpil, Muge Tamar, Hatice Karasoy, Tezan Bildik, Eyup S. Ercan, and Ahmet Gockay. "Zuclopenthixol-Induced Neuroleptic Malignant Syndrome in an Adolescent Girl. Clinical Toxicology. Informa Healthcare, date=2007": 277-280.
- Sharp, Kelly (2006). "Hypertension: Just the Facts". Clinical Journal of Oncology Nursing 10: 727-729.
- Cappacio, F P. , and N D. Markandu (1997). "Double-Blind Randomised Trial of Modest Salt Restriction in Older People". Lancet 350: 850-854.
- Krachler, M, and E Rossipal (1999). "Trace Elements Transfer From Mother to the Newborn - Investigations on Triplets of Colostrum, Maternal and Umbilical Sera". European Journal of Clinical Nutrition 53: 486-494.
- "Physics Update. " Physics Today June 1996: 9.
- "Visual Elements: Group 1 - The Alkali Metals. " Visual Elements. Royal Society of Chemistry. <http://www.chemsoc.org/Viselements/pages/data/intro_groupi_data.html>.
See also
External links
- Science aid:Alkali metals A simple look at alkali metals
- Doc Brown, Alkali metals
- Atomic and Physical Properties of the Group 1 Elements An in-depth look at alkali metals
| Alkali metals | Atomic numbers in black are solids | Solid borders indicate primordial elements (older than the Earth) | Dashed borders indicate natural radioactive elements with no isotopes older than the Earth |
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