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 sulphur

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Answers

2015-11-17T21:43:19+05:30
Mg and ca is the answer . Mg and ca
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