Force responsible to hold atoms together in a compound is called?

Which of the following have their outer most shell complete in atomic form?

Which one shows high %age of the ionic character?
 

Energy of atom in compound is?

When 2 lone pair and 2 bond pair are around the central atom reduction in the bond angle is up to?

Measurement of the degree of polarity is?

A specie with maximum number of unpaired electrons?
 

Molecular orbitals are filled according to?

In O2 each oxygen atom is hybridized?

The molecule having ?-bond?