what are s block elements? discuss the following in case of alkali metals (I) electronic configuration (ii) atomic size (iii) ionization enthalpy(long answer type question)..... please give me right answer
Answers
Answer: The s-block elements of the Periodic Table are those in which the last electron enters the outermost s-orbital. As the s-orbital can accommodate only two electrons, two groups (1 & 2) belong to the s-block of the Periodic Table.
(i) The electron configuration is the distribution of electrons of an atom or molecule in atomic or molecular orbitals. All the alkali metals have one valence electron (ns1) outside the noble gas core. The loosely held electron in the outermost valence shell of these elements makes them most electro-positive metals.
(ii)Atomic size is the distance between the centre of the nucleus of an atom and its outermost shell. The alkali metal atoms have the largest size in their respective periods of the periodic table. Atomic radii and ionic radii increase with atomic number as we move from Li to Cs.
(iii)Ionization enthalpy of an element can be defined as the amount of energy required to remove an electron from an isolated gaseous atom in its gaseous state. The alkali metals, which make up the extreme left-hand file, have ionization energies ranging from 124.3 kilocalories per mole in lithium to 89.7 kcal/mole in cesium.
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