Periodic Properties Review

First in class we decided that we would take the chemistry lab test on Wednesday. Next we went over the Periodic Properties 2 worksheet (pages 12 and 13). On page twelve we went over the first five questions, they compared the first two columns of the periodic table (Alkali Metals and Alkaline Earth Metals). Remember: columns are the rows moving from top to bottom, they are sometimes also called groups. Mrs. Mandarino also noted that we must know what the term valence e- means; which is the outermost e-. (This word will be used on the test tomorrow).

Then we went over page thirteen; we firsts discussed electronegativity. Electronegativity is an atom's ability to attract a shared e-. Once a bond of valence electrons is made, both atoms will share the electrons in a shared e-.

Factors that will affect electronegativity:

• Amount of energy levels (atomic size); Less energy levels=valence electrons will be closer to nucleus=smaller atom will "hog" shared e- more.
• Shielding electrons; more shielding electrons=weaker pull from nucleus=atom will not "hog" shared e-.
• Number of protons in nucleus of atoms that are in the same period; greater pull from nucleus=smaller atom will "hog" shared e- more.

When going down-electronegativity will decrease.

Why?

-> valence e- are further from the nucleus=weaker pull=atom will not hog shared electron.

When going across-electronegativity will increase.

Why?

-> valence e- are closer to nucleus=stronger pull=atom will "hog" shared e-.

The Periodic Properties Review sheet is under the Unit 3 Periodicity Assignments. If you click on it, all the questions are answered and done for you. If you don't understand any of the questions, be sure to look back at all the worksheets we were given (pages 1-13) will help, also look through the fill in the blank worksheets we did in class. If you want extra practice or more to review print the Periodicity Practice Exam under the Unit 3 Periodicity Assignments.

*Remember: if you're having trouble always go back to atomic size.*

Also: The test is tomorrow and and the lab test was moved to Wednesday.