Cat Video and Alkali Metals http www youtube

Cat Video and Alkali Metals http: //www. youtube. com/watch? v=fzzjg. BAa. WZw https: //www. youtube. com/watch? v=uixx. Jt. JPVXk (minute 1: 00)

Creating a Positive Learning Environment for Everyone Be respectful of your classmates n Save conversation for clicker portions of lecture n Put cell phones in “airplane” mode n Turn off tablets n Close laptops n

Announcements n n n Lon-capa HW 6 – Type 1 due Monday (11/27) and Type 2 due Wednesday (11/29) by 7 pm “Lab 5: Modern Atomic Theory” write-up due Friday in discussion Textbook HW and Pre-lecture Assignment due as usual

Clicker #1 How many of the following statements are true concerning an electron in its ground state? I. The electron must be in its lowest-energy state. II. Energy must be applied to the electron in order to excite it. III. The electron must be located on the nucleus of an atom. IV. The electron can release energy to obtain a lower ground state. A) 0 B) 1 C) 2 D) 3 E) 4

Electrons n n Electrons are most likely to be found near the nucleus Electrons could be anywhere (very far even) We do not know how the electron moves ORBITALS = regions of 90% probability

Clicker #2 How many electrons can fit in a set of d orbitals in the third energy level? How many electrons can fit in a set of f orbitals in the fourth energy level? A) 1; 1 B) 2; 2 C) 5; 7 D) 10; 14 E) 15; 28

Electron Configurations and the Periodic Table n=1 H n=2 Li Be He B C

Clicker #3 Why is diagram #1 preferred over diagram #2? diagram #1 A) B) C) D) diagram #2 Because spreading out between orbitals of equal energy will minimize electron-electron repulsions. Because each orbital “wants” an electron and this way two of the orbitals will be “happy”. Because this way there are fewer electrons in the element so the nucleus can have a greater positively charged pull overall. Because this arrangement allows us to better predict the wavelength (and thus color) of light that will be emitted to return to its ground state.

Electron Configurations and the Periodic Table n=3 Na

Electron Configurations and the Periodic Table n=4 K

Clicker #4 What comes next in potassium’s electron configuration? A) 3 s 1 B) 3 d 1 C) 4 s 1 D) 4 p 1 E) 4 f 1

Electron Configurations and the Periodic Table S Mn

Clicker #5 How many unpaired electrons does sulfur contain in its ground state? A) 0 B) 1 C) 2 D) 3 E) 6

Valence Electrons n Highest or outermost energy level electrons n n n Where the chemistry happens! Look at principal quantum level n Sulfur: 1 s 22 p 63 s 23 p 4 n n Valence electrons are in n = 3 level Valence electrons = 2 + 4 = 6 electrons