AnelementX hassamenumberof electronsin the firstand the fourthshell as wellas in thesecondandthe thirdshell. (a) Writedownthe electronic configurationof the element. ( b) Writedown thegroupnumberand theperiodto whichit belongs ( c)What is thevalencyof theelement ? (d )Willit formionicor covalentcompoundwith theelement Y (2,8,6) ? ( e)What isthe natureof the oxides ofX and Y ?

AnelementX hassamenumberof electronsin the firstand the fourthshell as

1.	AnelementX hassamenumberof electronsin the firstand the fourthshell as wellas in thesecondandthe thirdshell. (a) Writedownthe electronic configurationof the element. ( b) Writedown thegroupnumberand theperiodto whichit belongs ( c)What is thevalencyof theelement ? (d )Willit formionicor covalentcompoundwith theelement Y (2,8,6) ? ( e)What isthe natureof the oxides ofX and Y ?
Answer» SOLUTION :(a) Weknow that the MAXIMUMNUMBER OFELECTRONS in theIstand 2ndshell are 2and 8respectively.Since3rdshellhas thesamenumberof electrons as the2ndshelltherefore3rdshellalsohas 8electrons. Further since4thshellhas thesamenumberof electrons as the1stshelltherefore4thshellhas TWOELECTRONS. Thereforethe electronicconfigurationof the element X is 2,8,8,2Actually theelementXis Ca. (b) Sincein theelementX thevalenceelectrons are presentin the fourthshell ,thereforethe periodofelementX is 4.Furthersinceis has twoelectrons in thevalenceshellthereforeitsgroupnumberis 2. ( c) Valenceyof theelementX ( 2,8,8,2)i.e., Ca hastwoelectrons moreandtheelementY (2,8,6 ) i.e., Shas twoelectronslessthan thestableelectronicconfigurationof thenearestgasargon(2,8,8)thereforeXtransfers twoelectrons to Yto formioniccompound. (e )SinceX isa metaltherefore its oxideis basici.e.,CaO. SinceY is anon- metalthereforeitsoxide isacidic i.e.,`SO_(2)" or" SO_(3)`