The pair of elements which is not placed in the same group in Mendeleev's periodic table is:

1. Sc, Ga
2. Mn, Br
3. Nb, Sb
4. Rb, Cd

Subtopic:   Evolution of Periodic Table |
From NCERT
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In Mendeleev's periodic table, a number of series and groups are X and Y respectively. X and Y are:

1. X=12, Y=9
2. X=8, Y=9
3. X=8, Y=8
4. X=12, Y=8
Subtopic:   Evolution of Periodic Table |
From NCERT
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