S-Block

1 Subject: Chemistry Class: XI Chapter: The s-Block factors happen concepts 1. The s-block elements of the periodical table ar those in which the last negatron enters the outmost s-orbital 2. Elements of group1 argon called alkali metals and elements of group 2 are called alkalescent earth metal 3. Group1 elements: Alkali metals (i) Group 1 elements are called alkali metals because they form hydroxides on reaction with wet which are strongly alkaline in nature (ii) The universal electronic for alkali metals is [noble gas] ns1 Electronic configuration of alkali metals: Element type Atomic Number Lithium Sodium kilobyte rubidium Caesium Francium Li Na K Rb Cs Fr 3 11 19 37 55 87 Electronic configuration [He]2s [Ne]3s [Ar]4s 1 1 1 [Kr]5s 1 1 1 [Xe]6s [Rn]7s (iii)Trends in properties of alkali metals: 1. Atomic and noggin radii: Alkali metals cast out the largest nuclear and ionic radii in their respective periods of the periodic table. On move dec k the group, the atomic and ionic radii annex story: As we move in a period, the atomic gas constant and ionic radius tend to go down due to incr palliate in the effective nuclear charge. Therefore alkali metals start out largest atomic and ionic radii in their respective group. On contemptible down the group at that place is increase in the number of shells .

Thus there is an increase in outperform between nucleus and outer(prenominal) electrons which eventually increases atomic and ionic radii 2. ionization enthalpies: Alkali metals have the lowest ionization enthalpy in each period. at heart the group, the ionization enthalpies of alkali metals decrease down the group Get th e index number of visual Impact on your si! de Log on to www.topperlearning.com 2 Explanation:Atoms of alkali metals are largest in their respective periods and therefore, the valence electrons are loosely held by the nucleus. By losing the valence electron, they nark a line stable noble gas configuration. This accounts for their ease to lose electrons and accordingly they, have...If you want to get a serious essay, order it on our website: OrderEssay.net

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