1. LecturePLUS Timberlake
Predicting Bond Type
Using Eneg Values
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2. LecturePLUS Timberlake
I CAN predict a bond type using Eneg values and identify diatomic elements.
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3. Diatomic Elements
Some elements, when not bonded to other elements, bond to another atom of their own kind. These are known as DIATOMIC ELEMENTS.
There are 8 naturally existing diatomic elements:
ALL of family 17 (Halogen Family).
Oxygen, Nitrogen and Hydrogen
These elements should be written as:
F2, Cl2, Br2, I2, At2, O2, H2, N2 when they are NOT part of a compound.

4. LecturePLUS Timberlake
Pure vs Polar Covalent
When two atoms share an electron, the ELECTRONEGATIVITY value of each atom determines how closely the electron is pulled toward one atom or the other.
Recall Electronegativity [Eneg] is the measure of the attraction one atom has for another’s valence electrons.
SEE CHART NEXT SLIDE FOR Eneg Values.
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5. Electronegativity Values
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6. LecturePLUS Timberlake
Determining Bond Type
To determine the type bond between any two atoms, find the difference between their Eneg values:
0 to 0.5  PURE Covalent – the e- is shared at an equal distance between both atoms.
0.51 to 1.99  POLAR Covalent – the e- is shared closer to one atom than the other…this gives the atom the e- is closest to a slightly NEGATIVE charge [delta -] and the one the e- is father away from a slightly POSITIVE charge [delta +].
2.0 or greater  the e- is completely transferred from one atom to the other and forms an IONIC BOND.
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7. LecturePLUS Timberlake
Practice Problems
Use Eneg values to predict the type of bond that would form between each pair of atoms:
1. Ca and Br ____________ 2. H and O ______________ Pb and S ______________ Au and S_______________ 5. Sn and I ______________ 6. C and H _______________
7. B and H _______________ 8. Fr and F _______________ 9. N and Al _______________ Sb and Cl ______________
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