what makes the bond in hf a polar bonds?
367163
F has more electronegativity. That means that F doesn't share electrons nicely.  It holds the electron closer and doesn't let H have it much.  This makes F more negative and H more positive.
585856
The bond energy is closely related to electronegativity.  It is well known in chemistry that covalent bonds involving fluorine, oxygen, and nitrogen (FON or phone) are the strongest possible bonds (in that order).  Following that within the halogens, is chlorine, bromine, and iodine.  Again, as the electronegativity is lower, the bond energy is lower and that bond is easier to break.  \n\nThis is why HI is much more reactive than HF; the bond involving iodine is weaker (lower bond energy) than that of fluorine.  \n\nSo strongest fluorine:\nF>Cl>Br>I
837976
A molecule's structure can determine both chemical and physical properties of the compound (or element).  For example, the water molecule is asymmetric along one axis, making the oxygen atom side negative, and the hydrogen atom side positive.  The water molecule is said to be polar, and it will dissolve other polar molecules (and ionic substances) much better than non-polar molecules.  The molecule is also very stable, so water doesn't react chemically very easily - it doesn't burn, for example.
858630
Ionic bonds are created by attraction of separated charges or differences in electronegativity.  This results in a dipole moment, which is a vector property, hence it is directional.
35463
To have a net dipole moment (a positive end and a negative end), a species has to have some charge (partial or full) and have some asymmetry.\n\nMany (not all) ions are spherically symmetric (a metal ion, for instance--Na+).\n\nHowever, hydroxide ion (HO-) has asymmetry along the H-O bond, so it can have a net dipole.
957540
You have three types of bonds (essentially)\n\nYou have ionic, non polar covalent, and polar covalent.  Each has a strength in bonding.\n\nIonic is the strongest.  These will have the highest melting points (just try to melt salt for instance).  The non polar covalent bonds tend to be liquids or gases at room temperature (very low melting points).  Examples of these would be Methane , Benzene, ethane etc.\n\nPolar covalent bonds have a stronger pull on the electrons and therefore tend to be higher in melting point than non polar and lower than ionic.
468805
in water: a molecule of water will hyrdoyse the iron ion creating an iron hydroxide ion and a hydronium ion.  If the water is evaporate you still have the same compound except with some water trapped in the crystal structure.\n\nin ammonia: a co ordination complex is formed using 6 ammonia ligands [Fe(NH3)6]NO2\n\nAnd i don't actually know what would happen in hyrochloric acid
833912
hmm...do i detect a slight hint of webassign?\n\nammonium chloride(NH1+ and Cl1-) that should tell you enough.\n\nAnd for polyethylene, let's just say it's non-polar...how much does that help? (provided that hydrogen bonding is a special form of dipole-dipole, and dipole moments only happen in polar molecule)
839080
(D) is the right answer because O is more electronegative than N and N is more electronegative than S. So H-O bond is more polar than H-N bond and H-N bond is more polar than H-S bond.
216835
Sp2 non-polar covalent bond
112370
H2S.  That's very similar to H2O (which we usually associate with H-Bonding).  HBr, HCl, and HF will ionize.  SiH4 is symmetric and Si has medium electronegavity, etc, such that it would be like methane (Si is in the same group as C).
680519
yes, it does because fluorine, being such an electronegative elements allows one of its lone pairs to become a bonding pair for another hydrogen to attach (other than its already used up bonding pair). and like the first quote HF has some of the strongest H-bonds due to the fluorine being one of most electronegative elements.
809957
The most polar bond will be between the atoms with the greatest difference in electronegativity.\n\nF2 has bond that is not polar since the electrons are equally shared between the two identical atoms. The electronegativity series is As<S<Br<F so the biggest difference is between As and F and the most polar bond is in AsF3.\n\nAs belongs to the same family as N. Thus in AsF3 it forms 3 single bonds and also has 1 lone pair. So the electron-group arrangement is tetrahedral but since there are only 3 identical bonds there will be a net dipole moment.\n\nI already explained why F2 has no dipole moment\n\nBrF3 has trigonal bipyramid electron group arrangment (3 bonds+2 lone pairs) but not corners are occupied by identical atoms (2 have lone pairs of Br) so the dipole moments do not cancel out and the molecule has a net dipole moment\n\nSF4 has again trigonal bipyramid electron group arrangement(4 bonds + 1 lone pair) with one lone pair at one of the corners so it has a net dipole moment\n\nSF6 has octahedral electron group arrangement (6 single bonds)\nand since all corners have F atoms the dipole moments of the bonds cancel each other and the molecule has no net dipole moment.
361732
Lewis structure of CH2Br2\n\nIts identical to the lewis structure of methane but just replace two hydrogen atoms with bromine atoms (remember to add the three lone pairs around both bromine atoms).\n\nNow about polarity:\n\nThe C-Br bond is then considered to be polar. Having bromine slightly negative and carbon slightly positive. Over all the molecule is polar.\n\nSymmetry:\n\nAnd yes dibromomethane (CH2Br2) has two planes of symmetry, one horizontal and one vertical. In order to verify this, you have to look at the molecule in three dimension and not two dimentional (as drawn on a paper)
825051
Covalent bonds, as in NH4+
953050
If the difference in the electronegativity between the two elements is less than 1.67, the bond will be covalent.\n\nNote: As to the statement that electronegative atoms don't form covalent bonds, that's nonsense.  ALL atoms are electronegative to some extent.  Just go look up the electronegativity series in any general chem. text.  Or check out this:\nhttp://dbhs.wvusd.k12.ca.us/webdocs/Bonding/Electroneg-Bond-Polarity.html
950410
Mainly H-bonding (intermolecular forces)