. The electrons in the atoms of four elements A, B, C and D are distributed in three shells having 1, 3, 5 and 7 electrons in the outermost shell re

State the period in which these elements can be placed in the modem periodic table. Write the electronic configuration of the atoms of A and D and the molecular formula of the compound formed when A and D combine

Best Answer



All these elements belong to the 3rd period as all these elements have three shells.

Element A:

Electronic Configuration 2, 8, 1

Valence electrons: 1           valency:1

Element D:

Electronic Configuration 2, 8, 7

Valence electrons: 7.          Valency:1

Molecular formula:


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