The electrons in the atoms of two elements X and Y are distributed in three shells having 1 and 7 electrons respectively in their outermost shells.
Write the molecular formula of the compound formed when X and Y combine with each other.

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 respectively in their outermost shells. Write the group numbers in which these elements are placed in the Modern Periodic Table. Write the electronic configuration of the atoms of B and D and the molecular formula of the compound formed when B and D combine.

Three elements having 7 electrons in their outermost shell

Two elements having a single electron in their outermost shell

Name three elements that have a single electron in their outermost shells.

Name two elements that have two electrons in their outermost shells.

The two elements X and Y have 5 and 7 valence electron respectively, what will be the formula of the compound formed by them?

Outermost shells of two elements X and Y have 2 and 6 electrons , respectively .If they combine the expected formula of the compound will be