Polar molecules have _.
A) an uneven distribution of charges around the molecule
B) atoms that are the same element
C) an even distribution of charges around the molecule
D) ionic bonds
The correct answer and explanation is:
The correct answer is A) an uneven distribution of charges around the molecule.
Polar molecules exhibit an unequal distribution of electrons, leading to regions of partial positive and negative charges within the molecule. This is primarily due to differences in electronegativity between the atoms involved in the bond. Electronegativity refers to an atom’s ability to attract electrons towards itself. When two atoms with different electronegativities form a covalent bond, the electrons are not shared equally. The atom with the higher electronegativity attracts the bonding electrons more strongly, creating a partial negative charge on that atom and a partial positive charge on the other. This results in a dipole, where one side of the molecule is more negative, and the other side is more positive.
For example, in a water molecule (H2O), oxygen is more electronegative than hydrogen. Therefore, the oxygen atom pulls the shared electrons closer to itself, making the oxygen end of the molecule partially negative and the hydrogen end partially positive. This polarity gives water many unique properties, such as its ability to dissolve various substances and its relatively high boiling point.
In contrast, nonpolar molecules have an even distribution of electrons. This typically occurs when atoms of the same element or atoms with similar electronegativities bond together, such as in diatomic nitrogen (N2) or oxygen (O2). In these cases, the electrons are shared equally, and no partial charges are created.
It is also important to note that polar molecules do not necessarily have ionic bonds. Ionic bonds occur when there is a complete transfer of electrons between atoms, usually between elements with significantly different electronegativities, like sodium (Na) and chlorine (Cl).