Question

The first seven groups of the periodic table are divided into sub-group A consisting of?

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Answer 1

Answer:

it consist of hydrogen in sub group A

Answer 2

Sub-group A in Mendeleev's periodic table consisted of electronegative elements.

What is Mendeleev's Periodic Table?

Dmitri Mendeleev is widely considered as the Father of the periodic table. In his primitive periodic table the arrangement of elements was based on increasing atomic masses in sharp contrast to today's arrangement of increasing atomic number.

His periodic table had nine groups arranged vertically and labelled as I, II, III, IV, V, VI, VII, VIII and 0. Except 0 and VIII, the first seven groups were divided into two subgroups - A and B. Subgroup A consisted of electronegative elements while subgroup B had electropositive, metallic elements.

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