-The type of bond in Br2 ( the electronegativity for Br is 2.8) is nonpolar covalent
-In drawing a Lewis Structure, each nonmetal atom except hydrogen should be surrounded by 8 electrons.
-The chemical bond formed when two atoms share electrons is called a covalent bond.
- If two covalently bonded atoms are identical, the bond is nonpolar covalent.
- When the atoms share electrons, the electrical attraction of an atom for the electron is called electronegativity.
- If atoms that share electrons have an unequal attraction for the electrons the bond is called polar.
- The greater the electronegativity difference between two bonded atoms the greater the percentage of ionic character.
- If the difference in electronegativity is between .5 and 2.1, the bond is polar covalent
- If the electronegativity is larger than 2.1 the bond is ionic.
- If the difference in the electronegativity is less than .5, the bond is nonpolar covalent
- In drawing a Lewis structure, the central atom is the least electronegative atom.
- If after drawing a Lewis Structure too many valence electrons have been used, the molecule probably contains one or more multiple covalent bonds.
- Multiple covalent bonds may occur in atoms that contain carbon, nitrogen, or oxygen
- The substance whose Lewis Structure shows three covalent bond is Ammonia or Boron Trihydride
- Bonding in molecules or ions that cannot be correctly represented by a single Lewis Structure is resonance
- To indicate resonance, a double-headed arrow is placed between a molecules resonance structures.
- Chemists once believed that a molecule that contains a single bond and a double bond split its time existing as one of these two structures. This effect became known as resonance.
- CF4 is carbon tetrafluoride.
- SiO2 is silicon dioxide.
- N2O4 is dinitogen tetroxide
- The model for predicting the shapes of molecule that is based on the VSEPR (valence, shell, electron, pair, repulsion) theory.
- The equal but opposite charges present in the two regions of a polar molecule create a dipole.
- CCl4, CO2, CH4 are nonpolar molecules. NH3, HCl, H2O are polar molecules.
- A polar molecule contains a region of positive charge and a region of negative charge.
- A molecule of Hydrogen Chloride is polar because the chlorine attracts the shared electrons more strongly than does the Hydrogen