Question

what is meant by immunity? how do we acqire immunity against diseases? Explain.

Answer 1

To know the valence you first have to know the atomic no. Of the elements and to calculate valence check how many no. Electrons are the in last cell and then subtract it from no. Of electrons that can put in that cell.. Let we take an example of carbon... Carbon has 6 valency and four electrons in L she'll which is outermost cell of carbon and we know in L she'll there can be 8element so 8-4 =4 so the valence of carbon is 4.

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