polar or non?

Question

i have to determine whether H-F is polar or nonpolar.......how do i know that? people say the electronegativity diffrence but how do i do that?

also whats Br-Br....nonpolar?polar?

thank u,
confused student

ok ut so if all the questions begin with "H" like H-O H-N H-Cl, they will all be polar??? since the H is allll the way to the left and as said before, its gonna increase...........?

Answer 1

Polar molecule = a molecule in which the polar bonds are disposed in such a way that it imparts an asymmetry to the molecule as a whole. That is, it gives the whole molecule a Dipole Moment:

example: water H-O-H has two polar bonds. Since this molecule is Bent, those two polar bonds ADD TOGETHER to produce a molecule with a dipole moment. That is, a polar molecule.

example: carbon dioxide O=C=O has two polar bonds also. Since this molecule is Linear, those two polar bonds ADD TOGETHER to cancel each other out, to produce a molecule with NO dipole moment. That is, a nonpolar molecule.

example: carbon tetrachloride CCl4 has four very polar bonds but these bonds are pointing to the corners of a tetrahedron, and form a very symmetric arrangement. The polarity cancels itself out, and the molecule is NONPOLAR.

Electronegativity is the ability of an atom to attract electrons to itself when combined with other atoms. The periodic trend of electronegativity is to increase from left to right (except for the noble gases) and from bottom to top. Thus fluorine is the most electronegative of all atoms. It is often useful to know the top four electronegative atoms. These are, in order, fluorine, oxygen, nitrogen, and chlorine. Hydrogen is a special, but important, case. If the periodic table were totally organized strictly by trends in electronegativity, it would fit between carbon and boron.

Electrons that are shared equally are nonpolar bonds. Shared electrons that are more attracted to one atom than the other are called polar bonds. The more electronegative atom is the negative pole and the less electronegative atom is the positive pole. Extreme examples on polar bonds might actually qualify as ionic bonds. The line between an ionic bond and a covalent bond is not absolute.

Therefore H - F is polar......large difference in electronegativity
and Br -Br is not polar beacuse it is symetrical so the charges cancel out.

Answer 2

H-F Polar toward the F because the F atom is going to pull on the H atom hard/stronger. F is the most electronegative atom if you look at a electronegative chart it is in the same way of the periodic table decrease right to left and top to bottom. Br-Br is a non polar molecule they pull on each other equally. Electronegative is the measure of the relative ability of bonded atoms to attract the shared electrons.

Answer 3

Electronegativity tends to increase from left to right, and from bottom to top of a periodic table.

Fluorine has a higher EN than hydrogen (as can be seen by it's position on the periodic table.) Therefore, H-F is polar.

Two bromine atoms bonded together both have the same electronegativity, therefore the bond is non-polar.

Answer 4

H-F is polar because some electrons are left unpaired. If there are no electrons left unpaired then the substance is non-polar. Therefore Br-Br is non-polar.

Answer 5

Non polar covalent..equal charges on both ends.