How to Identify a Type of Bonding or Element and its Characteristics *All molecules have London-Dispersion Forces or LD. They are the weakest intermolecular force.
Does it have eight valence electrons?
Valence electrons are the electrons on the outermost shells of atoms and determine the elements group on the Periodic Table.
Is it covalent?
A covalent bond is the sharing of
electrons between a metal and a non-metal.
Is it ionic?
An ionic bond is the transfer of electrons between two oppositely charged atoms.
No
Yes
No
Yes
No
Yes
Is it a covalent compound?
A covalent compound is a compound formed by covalent bonds. Covalent compounds include H2O, (water) CH4, (methane), and NH4+.(ammonium)
Is it an ionic compound? Ionic compounds are compounds formed from ionic bonds. Ionic compounds include Potassium Bromide (KBr), Cesium Fluoride (CsF), and LiCl (Lithium Chloride)
Return to starting point
If the element has eight valence electrons, then it is a Noble Gas.
Return to starting point
No Return to starting point
Yes
No
No
Return to starting point
Yes
If yes make a Lewis Diagram.
Lewis Diagrams show the bonding that exists in a molecule and its lone pairs of electrons. Before you make the Lewis Diagram add up all of the valence electrons that the molecule has. Valence electrons are the electrons on the outermost shells of the atom. For example, water has eight valence electrons. Then the determine the Central Atom. The central atom in a Lewis diagram is the one that can facilitate the most bonds. Oxygen can have two bonds and hydrogen can have one bond. In this case, oxygen is the Central Atom. Draw the atomic symbol for Oxygen and then extend two lines off of it and draw the two hydrogen atoms. One line represents one bond and one bond has two electrons. To complete the diagram and two pairs of dots to the Oxygen to show the other for electrons. These pairs of electrons are called lone pairs and they are atoms that are not in bonds. Two things to remember when drawing Lewis diagrams are the duet and octet rules. The duet rule means that atom must have two atoms and the octet rule means that an atom must have eight atoms. This diagram satisfies the octet rule because there are eight valence electrons from the lone pairs and bonds present.
Polar or Non-Polar Molecule?
Non-Polar Molecules have mostly non-polar bonds with and no lone pairs on their Central Atoms. A non-polar bond has an electronegativity less than or equal to .4. Electronegativity is the tendency of an atom to attract shared electrons to itself. Polar molecules have mostly polar bonds (Electronegativity is greater than .4) and lone pairs of electrons on their central atoms.
Ionic Forces?
Ionic intermolecular forces hold ions together in ionic solids.
Polar molecules can have a Dipole-Dipole (DD) Interaction or Hydrogen Bonds (H-bond). DD is the second strongest intermolecular force and occurs in polar molecules because partial positives and negatives must interact. H-bonds are DD interactions but they are the strongest intermolecular force and Fluorine, Nitrogen, or Oxygen must bonds with hydrogen for it to occur (FON). Polar molecules include Sulfur dioxide (SO2) and Ammonia (NH3). Also, both DD and H-bonds are permanent.
Non-Polar Molecule
LD forces are the predominant intermolecular force for non-polar molecules and the strength of it depends on the molecular weight. LD forces can sometimes be a little bit positive or negative on one side. Non-polar molecules include BH3 (Borane) and CO2 (Carbon Dioxide). This force is temporary too.
Return to starting point