Question

A linear molecule composed of two atoms is polar when

Answer 1

The best answer to this question is the greater the electronegativity difference, the more ionic the bond is. Bonds that are partly ionic are called polarcovalent bonds. Non polar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal.

Answer 2

Answer: there is a electronegativity difference between the two atoms.

Step-by-step explanation:

A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms. It is also defined as the bond which is formed due to the unequal sharing of electrons between the atoms. An electronegative atom is the one which attracts the shared pair of electron towards itself. Example:
`HF` is polar as florine is more electronegative than hydrogen and thus bears a partial negative charge and hydrogen bears a partial positive charge.

Non-polar covalent bond is defined as the bond which is formed when there is no difference of electronegativities between the atoms. It is also defined as the bond which is formed due to the equal sharing of electrons between the atoms. Example:
`H_2`