Two elements ‘A’ and ‘B’ have same number of electrons in their valence shells. The number of electrons present in the second last shell of atom ‘A’ is two times the number of electrons present in the second shell of atom ‘B’. A and B respectively are
(1) Aluminium and phosphorus
(2) Magnesium and calcium
(3) Silicon and carbon
(4) Oxygen and sulphu

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Answers

2015-07-29T19:48:57+05:30
Sillicon and oxygen i think.it is write ans
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