InterviewSolution
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InterviewSolution
| 1. |
the difference between the maximum number of electrons that can be accommodated in 2nd and 3rd shell of an atom is: |
| Answer» <p>★Calcium is a S- block element . ( atomic number 20 )elements which have their last electron filled in the S subshell are called Sblock element .</p><p>★What u r saying is that when the 3rd shell can accommodate 18 electrons then why Calcium has 2,8,8,2 configuration .The Reason - ★Aufbau's Principle - Electrons dont fill continuously in a shell , they fill in subshells first , each shell has respective subshells .★ 1 st Shell has 1 subshell named S .( s can accommodate 2 electrons at MAX.)★2nd Shell has 2 subshell named S,P( P CAN accommodate 6 ELECTRON AT MAX)★3rd Shell has 3 subshell S,P and D.(D CAN ACCOMMODATE 10 ELECTRON AT MAX )and so on...★ Now the subshells are filled in this order I have shown in the picture .So , before the 3rd Shell is fully filled , 4th shell starts to fill after 3p subshell .HENCE AS only 3s and 3p are filled in Calcium from the 3 rd shell it has this configuration .</p><p>Overall : the formula gives the number of electrons in shell.but electrons fill subshell wise in an elements electronic configuration.</p><p>Electrons are filled by the (n+l) rule , n is the shell number and l is the subshell .</p><p>For S subshell , l = 0P subshell l = 1D subshell l = 2</p><p>the lower value of n+l fills first.if 2 values of n+l are same then the one with lower shell number is filled first</p> <p>Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that thenth shell can in principle hold up to 2(n2) electrons.[1]Since electrons areelectrically attractedto the nucleus, an atom's electrons will generally occupy outer shells only if the more inner shells have already been completely filled by other electrons. However, this is not a strict requirement: atoms may have two or even three incomplete outer shells. (SeeMadelung rulefor more details.) For an explanation of why electrons exist in these shells seeelectron configuration</p> <p>2nd shell hold 8 electron3rd shell hold 18 electron</p> <p>2nd shell 8 electrons and 3rd shell 18 electrons and the maximum number of Electrons in each shell in 2n2</p> | |