Periodic Table

[Audio] Hi everyone Today our topic is Periodic table Their elements and its periodic properties.

[Audio] In modern periodic table Elements are arranged in increasing order of their atomic number.

[Audio] Modern periodic law states that The physical and chemical properties of elements Are periodic function of their atomic number.

[Audio] There are eight groups and seven periods in periodic table. First two periods are short periods Remaining periods are long periods.

[Audio] The modern periodic table are as shown in The horizontal rows are called periods There are seven period in periodic table The vertical columns are groups There are eight groups in periodic table.

[Audio] Group one a elements Group one a elements are called alkali metals This is because when they react with water to form strong base. Group two a elements are called alkaline earth metals Because they are insoluble in water and found in earth crust. Group four a elements are called semiconductors Because they become insulator at zero kelvin And when temperature increases it becomes conductor..

[Audio] Group seven a elements are called halogens Because they react with alkali to form salt Group eight a elements Group eight a elements are called noble gases Because they are inert in nature And do not participate in chemical reaction.

[Audio] Group Number tell us Number of electrons in its outermost shell Period number tell us Number of shell in an atom.

[Audio] There are four blocks in periodic table; S-block elements: Group one A and two A elements are called s-block elements, because their outermost electronic configuration are in s orbital. p-block elements: Group III-A to VIII-A elements are called p-block elements, because their outermost electronic configuration are in p orbital. d-block elements: Group one B to eight b elements are called d-block elements, because their outermost electronic configuration are in d orbital. f-block elements: lanthanide and actinide series are f-block elements, because their outermost electronic configuration are in f orbital..

[Audio] Periodic properties. PERIODIC PROPERTIES.

[Audio] SHIELDING EFFECT: THE REDUCTION IN FORCE OF ATTRACTION BETWEEN NUCLEUS TO OUTERMOST SHELL DUE TO PRESENCE OF INNER SHELL IS CALLED SHIELDING EFFECT OR SCREENING EFFECT.

[Audio] TRENDS: As we move down the group number of shell increases decrease the force of attraction between nucleus to outermost shell So shielding effect increases. AS WE MOVE FROM LEFT TO RIGHT NUMBER OF SHELL REMAINS CONSTANT SO SHIELDING EFFECT REMAINS CONSTANT..

[Audio] ATOMIC SIZE: ATOMIC SIZE CAN BE DEFINED AS SIZE OF ATOM OR "THE DISTANCE BETWEEN NUCLEUS TO OUTERMOST SHELL.".

[Audio] TRENDS: As we move down the group number of shell increases increase the distance between nucleus to outermost shell so atomic size increases. as we move left to right in a period the number of shell remains constant Electrons added in the same shell increase the force of attraction between nucleus to outermost shell so atomic size decreases..

[Audio] IONIZATION ENERGY: THE MINIMUM AMOUNT OF ENERGY REQUIRED TO REMOVE ELECTRON FROM ITS OUTERMOST SHELL OF ISOLATED GASEOUS ATOM IS CALLED IONIZATION ENERGY.

[Audio] TRENDS: AS WE MOVE DOWN THE GROUP ATOMIC SIZE INCREASES DECREASE THE FORCE OF ATTRACTION BETWEEN NUCLEUS AND OUTERMOST SHELL IT IS EASY TO REMOVE ELECTRON FROM OUTERMOST SHELL SO IONIZATION ENERGY DECREASE DOWN THE GROUP AS WE MOVE FROM LEFT TO RIGHT ATOMIC SIZE DECREASE INCREASE FORCE OF ATTRACTION BETWEEN NUCLEUS TO OUTERMOST SHELL IT IS VERY DIFFICULT TO REMOVE ELECTRONS FROM OUTERMOST SHELL SO IONIZATION ENERGY INCREASES..

[Audio] ELECTRON AFFINITY: ELECTRON AFFINITY CAN BE DEFINED AS THE AMOUNT OF ENERGY RELEASED WHEN AN ELECTRON IS ADDED TO OUTERMOST SHELL OF NEUTRAL ATOM TO FORM ANION.

[Audio] TRENDS: AS WE MOVE DOWN THE GROUP ATOMIC SIZE INCREASES DECREASE FORCE OF ATTRACTION BETWEEN NUCLEUS TO OUTERMOST SHELL IT IS EASY TO ADD ELECTRON IN OUTERMOST SHELL SO ELECTRON AFFINITY DECREASES AS WE MOVE FROM LEFT TO RIGHT ATOM ATOMIC SIZE DECREASES INCREASE FORCE OF ATTRACTION BETWEEN NUCLUS TO OUTERMOST SHELL IT IS DIFFICULT TO ADD EXTRA ELECTRON IN THE NUCLEUS SO ELECTRON AFFINITY INCREASES FROM LEFT TO RIGHT.

[Audio] ELECTRONEGATIVITY: THE TENDENCY OF AN ATOM TO ATTRACT THE ELECTRONS TOWARDS ITSELF IS CALLED ELECTRONEGATIVITY. " FLUORINE IS THE MOST ELECTRONEGATIVE ELEMENT ITS VALUE is 4".

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