12: Color of the compoundsĪll the compounds of alkali metals are colorless except those compounds in which the negatively charged part of the molecule is colored.įor example KMnO4 and K 2Cr 2O 7 are the colored compounds. This property of alkali metals is called the flame test. Whenever the alkali metals are heated on the flame, these give characteristic colour to the flame. The alkali metals lose one electron from the outermost orbital and show +1 oxidation states. These free electrons are responsible for electrical conductivity. 9: Electrical conductivityĪlkali metals have free electrons in the crystal lattice. The melting and boiling points decrease down the group. These low values are due to weak interatomic bonds in the solid-state. 8: Melting and boiling pointsĪlkali metals have very low melting and boiling points. The value of densities increases down the group from Li to Cs. ![]() Li, Na, and K have densities less than that of water. The alkali metals have low densities as compared to other metals of the periodic table. 6: ElectronegitivityĪlkali metals are the least electronegative, and this decrease down the group because of an increase in atomic size. 5: Electron affinityĪlkali metals have low electron affinities and the values decrease down the group because of an increase in atomic size. 4: Ionization energiesĪlkali metals have low ionization energies and values decrease down the group with an increase in size. Their atomic radii and ionic radii also increase down the group systematically. The atomic volumes of the alkali metals increase down the group. This luster is quickly tarnished as soon as metal comes in contact with the atmosphere. When alkali metals are freshly cut, they have a bright luster. These can be easily cut with a knife and can be fused. 1: Physical stateĪlkali metals are extremely soft. General properties of alkali metals General properties of alkali metals Physical properties of alkali metals and their trends in the periodic tableĪlkali metals show similarity and gradual variation in physical properties in the periodic table as follows. These can lose one electron easily and attain the electronic configuration of inert gases. Remember by s-block elements mean their outermost electron will enter the s-orbital.īy 1-A group means the alkali metals have one electron in their outermost s-orbital.įollowing is the electronic configuration of alkali metals.Įlectronic configuration of alkali metalsįrom the above image, it is clear that the alkali metals have only one electron in the outermost s-orbital, hence showing the valency of one. Keeping in view the rules for the electronic distribution, all of these alkali metals have one electron in their outermost s-orbital. Electronic configuration of alkali metals It has been prepared artificially in the laboratory. Occurrence of franciumįrancium has not been found in nature. Small amounts of rubidium and cesium are found in the deposits of potassium. Each of these constitutes about 2.4% of earth’s crust. Na and Potassium are the most abundant among the alkali metals. Spodumene whose formula LiAl(SiO 3) 2 is an important commercial source of lithium. These minerals are widely scattered over the earth. The deposits of lithium are found in the form of complex minerals. Important minerals of alkali metals Deposits of lithium NaCl NaNO 3 Na 2CO 3.H 2O Na 2CO 3.2NaHCO 3.2H 2O Na 2B 4O 7.10H 2O ![]() Rock salt or Halite Chile saltpeter Natron Trona Borax LiAl(SiO 3) 2 Contains 3.8-5.6 % of lithium Important minerals of alkali metalsįollowing are the names and formulas of some common minerals of alkali metals. ![]() Most of the earth’s crust is composed of insoluble aluminum silicates alkali metals. This is due to the reason that are highly reactive. Occurrence of alkali metalsĪlkali metals don’t occur free in nature. These produce a strong alkaline solutions in water. The reason is that these metals particularly Na and K are present in the ashes of the planet. The name alkali came from the Arabic root which means ashes. These are highly reactive metals that Na metal ignites as it comes in contact with atmospheric oxygen. These are known as s-block elements as their outermost orbitals are s and only one electron is present in it. The elements of group I-A except hydrogen whose oxides and hydroxides are strong alkalies are called alkali metals. 5: Reaction with electronegative elements.Chemical properties of alkali metals and their trends in periodic table.Physical properties of alkali metals and their trends in the periodic table.Electronic configuration of alkali metals.
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