1. 1.6 Atomic Orbitals General Chemistry review
The type or orbital be identified by its shape
An orbital is a region where there is a calculated 90% probability of finding an electron. The remaining 10% probability tapers off as you move away from the nucleus
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

2. 1.6 Atomic Orbitals
Because they are generated mathematically from wavefunctions, orbital regions can also be (–), (+), or ZERO
The sign of the wave function has nothing to do with electrical charge.
In this p-orbital, there is a nodal plane. The sign of the wavefunction will be important when we look at orbital overlapping in bonds.
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

3. 1.6 Atomic Orbitals
Electrons are most stable (lowest in energy) if they are in the 1s orbital
The 1s orbital is full once there are two electrons in it. Why can’t it fit more?
The 2s orbital is filled next. The 2s orbital has a node. WHERE?
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

4. 1.6 Atomic Orbitals
Once the 2s is full, electrons fill into the three degenerate 2p orbitals
Where are the nodes in each of the 2p orbitals?
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

5. 1.9 Hybridized Atomic Orbitals
Given the electron configuration for C and H, imagine how their atomic orbitals might overlap
Would such orbital overlap
yield methane?
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

6. 1.9 Hybridized Atomic Orbitals
To make methane, the C atom must have 4 atomic orbitals available for overlapping
If an electron is excited from the 2s to the 2p, will that make it suitable for making methane?
If four H atoms were to come in and overlap with the 2s and 2p orbitals, what geometry would the resulting methane have?
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

7. 1.9 Hybridized Atomic Orbitals
The carbon must undergo hybridization to form 4 equal atomic orbitals
The atomic orbitals must be equal in energy to form four equal-energy symmetrical C-H bonds
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

8. 1.9 Hybridized Atomic Orbitals
Should the shape of an sp3 orbital look more like an s or more like p orbital?
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

9. 1.9 Hybridized Atomic Orbitals
To make CH4, the 1s atomic orbitals of four H atoms will overlap with the four sp3 hybrid atomic orbitals of C
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

10. 1.9 Hybridized Atomic Orbitals
Consider ethene (ethylene).
Each carbon in ethene must bond to three other atoms, so only three hybridized atomic orbitals are needed
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

11. 1.9 Hybridized Atomic Orbitals
An sp2 hybridized carbon will have three equal-energy sp2 orbitals and one unhybridized p orbital
Which is lower in energy, the sp2 or the p? Why?
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

12. 1.9 Hybridized Atomic Orbitals
The sp2 atomic orbitals overlap to form sigma (σ) bonds
Sigma bonds provide maximum HEAD-ON overlap
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

13. 1.9 Hybridized Atomic Orbitals
The unhybridized p orbitals in ethene form pi (π) bonds, SIDE-BY-SIDE overlap
Practice with conceptual checkpoint 1.20
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

14. 1.9 Hybridized Atomic Orbitals
Consider ethyne (acetylene).
Each carbon in ethyne must bond to two other atoms, so only two hybridized atomic orbitals are needed
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

15. 1.9 Hybridized Atomic Orbitals
The sp atomic orbitals overlap HEAD-ON to form sigma (σ) bonds while the unhybridized p orbitals overlap SIDE-BY-SIDE to form pi bonds
Practice with SkillBuilder 1.7
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e

16. 1.10 Geometry Summary Practice with SkillBuilder 1.8
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.
Klein, Organic Chemistry 2e