Here we are publishing 50 most imortant focus point to remember from kerala SSLC Chemistry-chapter 1 periodic-table-and-electronic-configuration

SHELLS & SUBSHELLS

鈴猴笍In an atom there are main energy level called shells and sub energy levels called sub shells.

鈴猴笍The number of sub shells in each energy level is equal to its shell number.

馃攨s sub shells can accommodate 1 to 2 electrons

馃攨p sub shells can accommodate 1 to 6 electrons

馃攨d sub shells can accommodate 1 to 10 electrons

馃攨f sub shells can accommodate 1 to 14 electrons

馃専1s<2 s <2p<3s<3p<4s<3d<4p<5s<4d<5p<6s鈥︹︹︹
馃専1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s鈥︹︹︹︹︹︹.
馃専The electrons in an atom are distributed in the increasing order of the energies of sub shells. This is called sub shell electronic configuration.
馃専The maximum number of electrons accommodated in each sub shells s-2, p-6, d-10, f-14.

HOW TO FIND BLOCKS AND GROUP NUMBER

BLOCK OF ELEMENT


鉁达笍Block of elements= The sub shell to which the last electron is entered

鉁达笍Half filled d sub shells are more stable.

鉁达笍Completely filled d subsheel are more stable.

Group Number



鈻讹笍s block elements No of electrons in the last s sub shell

鈻讹笍p block elements No of electrons in the last p sub shell +12

鈻讹笍d block elements No of electrons in the last s sub shell + No. of electrons in the inner d sub shell.

P BLOCK ELEMENTS

*锔忊儯 13 to 18 group elements are present in p Block

*锔忊儯1 to 6 electrons are present in p subshell

*锔忊儯Elements in the solid, liquid and gaseous state at room temperature are included in this block

*锔忊儯In p block elements , less reactive elements(more stable
elements) are present in the 18
th group (Noble gases)

*锔忊儯Elements with Positive and negative oxidation state are present in p block

*锔忊儯P block elements usually show higher ionization energy than the s block elements.

*锔忊儯In p block elements, the highly reactive elements are

D BLOCK ELEMENTS

馃挔Groups 3 to 12 belongs to 鈥榙鈥 block elements of periodic table

馃挔From 4 the period onwards the 鈥榙鈥 block elements beigns.

馃挔鈥榙鈥 block elements are called transition elements

馃挔The last electron is filled in the penultimate shell

馃挔The group number of the 鈥榙鈥 block elements will be the same as the sum of electron in the outer most 鈥 s鈥 subshell and inner 鈥榙鈥 sub shell 飩 鈥榙鈥 block elements are called transition elements

CHARACTERSTICS



馃挔They show different oxidation state

馃挔They form coloured compounds

馃挔The last electron is filled in the penultimate shell

馃挔They show similarities in properties not only in group but also in period

馃挔Most of them are metals

馃挔Most of the coloured salts are compounds of
transition elements.
馃挔The colour is due to the presence of transition metals ions present in these compounds.

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