Homework (coal ash writing) on the front table. And get the two packets, soldier.

Get your colors from yesterday

Fe Man here, Please get a handout packet on Periodic Trends and a light colored pencil or crayon.

Schedule for the coming week.. Thursday (tomorrow) Next Tuesday

Unit 4 Extra Credit As Hank explained in the Crash Course video, there are other ideas about how to organize a Periodic Table of the elements. For extra credit on the Unit 4 Test, find one of these other versions and reproduce it. In addition, write a short paragraph explaining the main idea behind this different approach, and the different approach’s respective strengths and weaknesses. (hint – one of them is SUPER easy, but you have to think about it) Due Monday, March 3rd

Where we are Or at least, should be…

Groups and Periods

Metals, Nonmetals, Metalloids

Solids, Liquids, Gasses

Groups, & Valence Numbers Lanthanides Actinides

Valence Electrons Everyone wants to have 8 (H, Li and Be are cool with 2) All members of Group 1 have one, the easiest thing for them to do is lose the electron. Their next energy level down has 8 valence electrons. All members of Group 7 have seven. They all want one, therefore filling their valence shell. Any element from Group 1 + any element from Group 17 = a salt. All members of group 2 have 2, all members of group 16 need two. Generally speaking, one atom from any group 2 element will combine with one atom from any group 16 element, and everyone will be happy.

Periodic Trends: All are based on the structure of the atoms. Remember that. That means that all are dependent on the relationship between and number of protons and electrons.

Periodic Trends: You are responsible for knowing: Reactivity Atomic radius Ionization energy Electronegativity You need to know what each is, how it trends on the periodic table, and how each relates to atomic structure.

First: Reactivity… In other words, how “reactive” an element is when it plays with others. All due to electrons.

Who’s reactive? Groups? Elements within groups? Why? Shielding Effect

Who’s reactive? Shielding Effect – the further an electron is from the nucleus, the less influence the nucleus has on that electron. This allows for many of the trends seen in the Table.

Reactivity Trend

Noble Gasses are essentially nonreactive

Again…berks! By the end of the period you’ll have a filled in sheet explaining: Atomic radius Ionization energy Electronegativity Draw large arrows on your cover page as you learn a new trend for each.

Atomic Radius

Atomic radius: Can you explain this?

Ionization Energy: higher, harder it is to lose an electron

Ionization Energy. Focus on groups and periods.

Going down a group…

Electronegativity – the more electronegative, the more it “wants” an electron.

Electronegativity

Ion sizes – Ions are in gray. Cations smaller than atoms, anions are larger than atoms

Ion size – based on structure, again. Cation – fewer electrons, loss of an energy level (think about it), the + nucleus can pull the electrons in tighter and the atom is smaller. Anion – more electrons, more for each electron to repel in the orbitals, so they need more space.

Big picture – all based on the specific atomic structure.

Landmarks: Know ‘Em. Most electronegative: Fluorine Lowest First Ionization energy: Potassium Largest Atomic Radius: Francium Smallest Atomic Radius: Hydrogen