Comic Polar Bear

The BARE ESSENTIALS of POLARITY You don't have to go to the ends of the earth to find POLAR MOLECULES. They're all over the place. A polar molecule is just a molecule with a difference in electrical charge between two ends. The electrical imbalance of POLARITY is caused by differences in ELECTRONEGATIVITY between atoms. Electronegativity is the ability of an atom/nucleus to attract bonding electrons toward itself.   In HCl, the bonded pair of electrons spends more time near the chlorine's nucleus because chlorine is more electronegative than hydrogen.   The periodic table shows a general trend in the electronegativity of the elements. Electronegativity tends to rise as you move "northeast" on the periodic table, and fall as you move "southwest." Note: The noble gasses, in the periodic table's far right column, are often assigned an electronegativity value of zero because they are relatively nonreactive.   When two atoms with unequal electronegativity values bond, they do not share the bonding electrons evenly. The bonding electrons spend more time around the more electronegative atam, creating a PARTIAL NEGATIVE CHARGE on that atom. The other ofum then has a PARTIAL POSITIVE CHARGE, and the band is polar, POLARITY IS UNFAIR! OH, TRY TO BE MORE POSITIVE, + So the polarity of a bond is a function of the difference between the electronegativity values of two bonding atoms. Bonded atoms with equal electron-attracting strength will have nonpolar bonds, However, if the electronegativity of two bonded atoms is unequal, then their bond will be polarized-maybe a little + maybe a lot. Because the elements have such varying electronegativities and can come Together in so many different combinations, there is really & CONTINUUM OF POLARITY IN BONDING. For convenience, we can break the continuum down into three categories: (1) nonpolar covalent, (2) polar covalent, and (3) isnic NONPOLAR COVALENT 00 (O is double-bondad) The clearest examples of nanpolar covalent bonds are those between identical atoms, such as H. Ng. Oz, or Cls Bonds between atoms with nearly the some electronegativity value such as carbon and hydragen atoms, are usually also considered numpalur. Remember, this is really a continuum, and conventional distinctions are somewhat artificial POLAR COVALENT +HF pertial negative charge partial proitive charge In a poter covalent bond, two atoms still share banded pairs of electrons, but those electrons are decidedly mere attracted to one stom than the other. Examples include honds between carbon and axygen atoms, or between hydrogen and fluerine atome IONIC positive charge +Na CI nerative cherbe MIT2001 At the extreme of difference in electronegativity, polar covalence shades into the winner-take-all situation of sonic bonding. The more electronegative atom seizes all the bonding electrons and becomes a negative ion, while the other atom becomes a positive ion. The opposite chargest on the ions attract each other Polar bonds between atoms constitute DIPOLES. Actually, the word "dipole" can refer to several different things that are relevant here: (1) the polarity of an individuel polar bond between atoms, (2) the net polarity of a polar molecule that may have several polar covalent bands within it, and (3) the polar molecule itself Confusing? Let's look at some examples: An N, malesule isn't as dipole (it's not a polar molecule), and it doesn't have any dipoles (palar bonds) within it. NN BOND NONPULAR MOLECULE: NONPOLAR HCI has a dipole (a polar bond) and it is a dipsie (a polar molecule) HCI BOND:+ MOLECULEI On the ather hand, CD, has twu dipoles (two polar) bonds), but the CO, molecule itself is not a dipole because its polar bands cancel each other out and make the molecule nonpolar overall. BONDS: ++ MOLECULE: NONPOLAR Like CO₂, H₂O his twe dipales (twe polar bonds). But because of H₂O's bent shape (caused by lone pairs of electrons on the oxygen atom), H₂O also has a dipale in the sense of an overall polarity. Sa H₂O is a dipole in the sense of being a polar molecule. H H The polarity of molecules can affect many of their other properties, such as their solubility, their boiling and melting points, and their odor, YOU SMELL PENGUINT WHY ARE WE IN THE COMIC STRIPT PENGUINT AND PALAR BEARS DON'T TEYEN LIVE AT THE SAME PALES SUITS ME!