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.
Which of the two is electropositive ?

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

The electrons present in the outermost shell of an atom are called_____ electrons.

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

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

Electrons in the outermost shell of an atom are called