Fill in the blank. Oxygen ionizes to become ― 2 instead of ― 1 because O^2- is more ___________   .

(i) Using the periodic trend, choose the more electronegative atom in each pair. For one pair, you'll need to look at the actual Pauling values. (ii) For which one? (iii) Why?

(b) N vs. O

(i) Using the periodic trend, choose the more electronegative atom in each pair. For one pair, you'll need to look at the actual Pauling values. (ii) For which one? (iii) Why?

(d) B vs. Si

Based on your answer to Assessment 2.22, would you expect a larger atom to be more or less electronegative than a smaller atom?

Without looking at Figure 2.20, use your intuition to estimate whether a bond is ionic, polar covalent, or covalent.

(a) Na―Cl

Using only your intuition, rank the following covalent bonds in terms of their polarity (1 = most polar; 6 = least polar). [You can use the periodic trend of electronegativity, but don't use actual numbers.]

(a) C―C

(b) C―O

(c) C―H

(d) C―F

(e) C―Cl

(f) C―S

Draw the Lewis structure for the following molecules. Be sure to calculate the formal charge of each atom as a way of confirming your structure is correct.

(b) HOBr

Draw the Lewis structure for the following molecules. Be sure to calculate the formal charge of each atom as a way of confirming your structure is correct.

(c) CF₄

Calculate the formal charge of the indicated atom in the following molecules or ions.

(d)

Calculate the formal charge of the indicated atom in the following molecules or ions.

(e)

Calculate the formal charge of the indicated atom in the following molecules or ions.

(f)

Draw the Lewis structure for the following ions. Be sure to calculate the formal charge of each atom to confirm that your structure is correct.

(b) H⁺

Draw the Lewis structure for the following ions. Be sure to calculate the formal charge of each atom to confirm that your structure is correct.

(c) BH₄^-

Draw the Lewis structure for the following ions. Be sure to calculate the formal charge of each atom to confirm that your structure is correct.

(d) AlCl₄^-

Calculate the formal charge of the indicated atoms in the ions shown.

Calculate the formal charge on the non-hydrogen atoms in the molecules shown. Use the arrow-pushing formalism to 'move' an electron pair such that it is shared between two (formerly) charged atoms. Your arrow should account for the formation of the molecule on the right from the molecule on the left.

You drew the Lewis structures of the following compounds and ion in Assessment 2.32. Predict their shapes around the central atom based on the Lewis structure.

(c) HCO₂H

You drew the Lewis structures of the following compounds and ion in Assessment 2.32. Predict their shapes around the central atom based on the Lewis structure.

(d) CO₃^2-

For the molecules shown, indicate the direction of the dipole moment.

(a)

For the molecules shown, indicate the direction of the dipole moment.

(b)

Hydrogen forms bonds without hybridizing. Why?

Use hybrid orbitals to draw the following molecules.

(a)

Use hybrid orbitals to draw the following molecules.

(b)

Use hybrid orbitals to draw the following molecules.

(c)

Use hybrid orbitals to draw the following molecules.

(d)

Rank the following molecules by the length of the indicated bond from shortest to longest.

(a)

(b)

(c)

The sulfur and oxygen in methanethiol and methanol are both sp³ hybridized. Why is the S―H bond longer than the O―H bond?

A molecular orbital diagram is shown for the C―Cl bond in chloromethane. If two more electrons were added to chloromethane, where would the electrons go?

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How might electrons be excited from π to π* based on the molecular orbital diagram shown? [This will be relevant in Chapter 21.]

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Each pair of structures represents two valid resonance structures. Use the arrow-pushing formalism to justify the formation of the one on the left from the one on the right.

(a)