The Wade’s rules can be applied to the naked clusters of p-block elements. According to Wade’s rules, the number of skeletal electrons in Pb52– cluster is :
12
In Wade’s rules each main-group vertex atom in a naked cluster keeps one exo-directed lone pair, so it contributes (v – 2) electrons to the skeleton, where v is its number of valence electrons. The charge of the cluster adds to the skeletal electrons.
Lead is in group 14 with v = 4 (6s26p2), so each Pb vertex supplies 4 – 2 = 2 skeletal electrons.
For Pb52–: skeletal electrons = 5 × 2 + 2 = 12, that is 6 skeletal electron pairs.
With n = 5 vertices and n + 1 = 6 pairs the cluster is closo, a trigonal bipyramid, as found in the Zintl ion Pb52–.
The value 22 is the total valence electron count (5 × 4 + 2), which still includes the 10 electrons of the five exo lone pairs, so it is not the skeletal count; 18 and 8 do not arise from any consistent counting.
Check: total valence electrons 22 minus the 10 lone-pair electrons on the five Pb atoms = 12 skeletal electrons, confirming the result.
Hence, 12.
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Important Questions from Mixed Topic (MH-SET)
.................... is a client server application that identifies each host on the internet with a unique user-friendly name.
Every OS has a ................ or .......... which primarily resides in the main memory of the computer to perform some of the basic functions of the OS.
(i) Kernel
(ii) Interface
(iii) Nucleus
(iv) Compiler
Codes:
Which of the following are referred to as low level language?
(i) Machine language
(ii) Assembly language
(iii) High level language
(iv) Natural language
Codes:
Match the following:
List I List II (a) New York Public Library (i) Shelv AR (b) Miami University Augmented Research Group (ii) Smart library (c) Oula University Library (iii) Wolf Walk (d) North Carolina State University (iv) Find the future Codes:
Which part of the QR code represents the encoded data?
