1. General, Organic, and Biological Chemistry Fourth Edition Karen Timberlake 3.6 Electron Arrangement in Atoms Chapter 3 Atoms and Elements © 2013 Pearson Education, Inc. Lectures

2. © 2013 Pearson Education, Inc. Chapter 3, Section 6 Electrons and Reactivity Atoms contain  a very small nucleus packed with neutrons and positively charged protons.  a large volume of space around the nucleus that contains the negatively charged electrons. It is the electrons that determine the physical and chemical properties of atoms. 2

3. © 2013 Pearson Education, Inc. Chapter 3, Section 6 Electron Energy Levels  Electrons surround the nucleus in specific energy levels.  Each energy level has a principal quantum number (n).  The lowest energy level, which is closest to the nucleus, is labeled n = 1.  The second-lowest energy level is labeled n = 2, the third n = 3, and so on. 3

4. © 2013 Pearson Education, Inc. Chapter 3, Section 6 Electron Energy Levels 4 Electron energy levels increase in energy and number as electrons get farther away from the nucleus. The higher the electron energy levels,  the more electrons they hold.  the more energy the electrons have.

5. © 2013 Pearson Education, Inc. Chapter 3, Section 6 Sublevels Within each energy level, we have sublevels that  contain electrons with identical energy.  are identified by the letters s, p, d, and f. The number of sublevels within a given energy level is equal to the value of the principal quantum number, n. 5

6. © 2013 Pearson Education, Inc. Chapter 3, Section 6 Energy Levels and Sublevels 6

7. © 2013 Pearson Education, Inc. Chapter 3, Section 6 Energy of Sublevels Within any energy level,  the s sublevel has the lowest energy.  the p sublevel follows and is slightly higher in energy.  the d sublevel follows the p and is slightly higher in energy than the p.  the f sublevel follows the d and is slightly higher in energy than the d. 7

8. © 2013 Pearson Education, Inc. Chapter 3, Section 6 Orbitals 8 Each electron sublevel consists of orbitals, which  are regions where there is the highest probability of finding an electron.  have their own unique three-dimensional shape.  can hold up to 2 electrons.

9. © 2013 Pearson Education, Inc. Chapter 3, Section 6 s Orbitals 9 We know that s orbitals have a spherical shape, centered around the atom’s nucleus.  The s orbitals get bigger as the principal quantum number, n, gets bigger.  The s orbitals can hold up to 2 electrons that must spin in opposite directions.

10. © 2013 Pearson Education, Inc. Chapter 3, Section 6 p Orbitals 10 There are three p orbitals in each energy level, starting with energy level 2. They  have a two-lobed shape, much like tying a balloon in the middle, and can hold 2 electrons.  are labeled x, y, and z.  increase in size as the value of n increases.

11. © 2013 Pearson Education, Inc. Chapter 3, Section 6 Sublevels and Orbitals Each sublevel consists of a specific number of orbitals.  An s sublevel contains one s orbital.  A p sublevel contains three p orbitals.  A d sublevel contains five d orbitals.  An f sublevel contains seven f orbitals. 11

12. © 2013 Pearson Education, Inc. Chapter 3, Section 6 Electron Capacity in Sublevels 12

13. © 2013 Pearson Education, Inc. Chapter 3, Section 6 Learning Check Indicate the number and type of orbitals in each of the following: 1. 4s sublevel 2. 3d sublevel 3. n = 3 13

14. © 2013 Pearson Education, Inc. Chapter 3, Section 6 Solution Indicate the number and type of orbitals in each of the following: Number Type 1. 4s sublevel 1 4s orbital 2. 3d sublevel 5 3d orbitals 3. n = 31 3s orbitals, and 3 3p orbitals, and 5 3d orbitals 14

15. © 2013 Pearson Education, Inc. Chapter 3, Section 6 Learning Check The number of 1. electrons that can occupy a p orbital is A. 1B. 2C. 3 2. p orbitals in the 2p sublevel is A. 1B. 2C. 3 3. d orbitals in the n = 4 energy level is A. 1B. 3C. 5 4. electrons that can occupy the 4f sublevel is A. 2B. 6C. 14 15

16. © 2013 Pearson Education, Inc. Chapter 3, Section 6 Solution The number of 1. electrons that can occupy a p orbital is B. 2 2. p orbitals in the 2p sublevel is C. 3 3. d orbitals in the n = 4 energy level is C. 5 4. electrons that can occupy the 4f sublevel is C. 14 16