Electronegativity and Bonding
What is electronegativity?
Electronegativity is the measure of an atom's tendency to attract shared electrons toward itself in a chemical bond.
What happens to bond length as bond order increases?
bond length decreases
What two types of elements typically form an ionic compound?
metal and non metal
What does a single line between two atoms represent in a Lewis structure?
a single bond
What theory is used to predict molecular geometry?
VSEPR Theory
As you move left → right across a period, what happens to electronegativity?
increases
Which is stronger: a single, double, or triple bond?
triple bond
What two factors make an ionic bond stronger according to Coulomb’s Law?
charge and radius of the atoms
What is the first step when drawing a Lewis structure?
How many electron domains surround the central atom in CH₄?
4 electron domains
Rank these bonds from least → most polar: C–C, C–H, C–O, C–F
C–C < C–H < C–O < C–F
Which has the shortest bond length: C–C, C=C, or C≡C? Explain.
c-c because it is a single bond so has a lower bond order and longer bond length due to its lower bond energy
Which should have the greater lattice energy: NaCl or CaO? Explain.
Ca O because Ca and O both have a charge of 2 and Na and Cl have a charge of 1
Draw the Lewis structure for C₂H₂. What type of bond connects the two carbon atoms?
Ctriple bondC with one H on each C
Is CO₂ polar or nonpolar? Explain using its molecular geometry.
nonpolar because even though it has polar bonds, it is a symmetrical molecule so the dipoles cancel out.
Why does electronegativity decrease as you move down a group?
because the radii of the atoms is increasing which causes the effective nuclear charge to be less as you go down a group
A bond has a higher bond energy and shorter bond length than another bond. What can you conclude about its bond order?
it has a higher bond order
Why does KBr have a higher lattice energy than KI?
Becasue Br us smaller than I
Draw the Lewis structure of HCN and determine the formal charge on each atom.
H-C triple bond N
formal charge:
H - 0 C - 0 N - 0
NH₃ is polar while CO₂ is nonpolar. Explain why using shape and dipole cancellation.
NH3 is in a trigonal pyramidal molecule while CO2 is linear. The N in NH3 has a lone pair which causes it to have a partial negative charge on it while the dipoles moments in CO2 cancel out due to its symmetry
C and Se have the same electronegativity (2.55). What type of bond would you expect between them, and why?
non polar because there is no difference in electronegativity values
N₂ has a triple bond while N₂H₄ has a single N–N bond. Compare their bond length and bond strength
the triple bond is shorter than the single bond.
The triple bond is stronger than the single bond
Rank NaCl, MgO, and Al₂O₃ from lowest → highest lattice energy and justify your ranking
NaCl, MgO, Al2O3 because of the charges on the cations
Draw the resonance structures of CO₃²⁻. What does resonance tell us about the actual C–O bonds?
2 C - O with 3 lone pairs and one c=o with 2 lone pairs and there are 3 resonance structures
Determine the molecular geometry, hybridization, bond angles, and polarity of SO₂. Explain your reasoning.
bent molecular geometry, sp2 hybridization, a bond angle of 120 (or 119), and it is a polar molecule