We are being asked to draw the MO energy diagram of Li_{2}^{+} and Li_{2}^{-} then predict which will exist in the gas phase.

**We will do the following steps**

*Step 1:* Calculate the total number of valence electrons present.

*Step 2:* Draw the molecular orbital diagram.

*Step 3:* Calculate the bond order of the molecule/ion. Recall that the formula for ** bond order** is:

$\overline{){\mathbf{Bond}}{\mathbf{}}{\mathbf{Order}}{\mathbf{}}{\mathbf{=}}{\mathbf{}}\frac{\mathbf{1}}{\mathbf{2}}\mathbf{[}\mathbf{\#}\mathbf{}\mathbf{of}\mathbf{}{\mathbf{e}}^{\mathbf{-}}\mathbf{}\mathbf{in}\mathbf{}\mathbf{bonding}\mathbf{}\mathbf{MO}\mathbf{}\mathbf{-}\mathbf{}\mathbf{\#}\mathbf{}\mathbf{of}\mathbf{}{\mathbf{e}}^{\mathbf{-}}\mathbf{}\mathbf{in}\mathbf{}\mathbf{antibonding}\mathbf{}\mathbf{MO}\mathbf{]}}$

**Part A**

Use the drawing of the MO energy diagram to predict the bond order of Li_{2}^{+}.

Express the bond order as an integer or fraction.

**Part B**

Use the drawing of the MO energy diagram to predict the bond order of Li_{2}.

Express the bond order as an integer or fraction.

**Part C**

Which molecules are predicted to exist in the gas phase?

A. Li_{2}^{}

B. Li_{2}^{+}

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Bond Order concept. If you need more Bond Order practice, you can also practice Bond Order practice problems.