1. Periodic Table and Periodicity
Chapter 14
Periodic Table and Periodicity

2. History of Periodic Table
Dmitri Mendeleev – listed the elements in several vertical columns in order of increasing atomic MASS. He left blanks in the table for elements that were not discovered yet.
Henry Mosley – Arranged elements on the periodic table in order of increasing atomic NUMBER.

3. Arrangement of Periodic Table
Periodic law – the properties of elements are periodic functions of their atomic number
Periods – horizontal rows; 7; correspond to energy levels
Groups/Families – vertical columns; “group A” Roman numerals correspond to the number of valence electrons
Group I – Alkali metals, Group II – Alkaline earth metals, Group VII – Halogens, Group VIII – Noble gases

4. Metals, Nonmetals, and Metalloids
Metals – everything to the left of the stairstep; including aluminum; does not include hydrogen
Properties: Have luster (shiny), good conductors of heat and electricity, malleable ( able to be pounded into sheets), ductile (able to be pulled into a wire), tend to lose electrons in chemical reactions, most are solids
Transition metals – middle block over to stairstep
Inner transition metals – bottom 2 rows; sometimes called “lanthanide series” and “actinide series”

5. Metals, Nonmetals, and Metalloids
Nonmetals – everything to the right of the stairstep; includes hydrogen
Properties – Dull, poor conductors, brittle, tend to gain or share electrons in chemical reactions, most are gases
Metalloids – either side of the stairstep; does not include aluminum

6. Periodic Trends
Atomic radius – half the distance between adjacent nuclei in a crystal of the element
Ionic radius
if atoms lose electrons, they become + and smaller (less electrons take up less space)
if atoms gain electrons, they become – and bigger (more electrons take up more space)
ionization energy – energy needed to overcome the attraction between the + charge in the nucleus and the – charge of the electron

7. Periodic Trends
electronegativity – the relative ability of an atom to attract electrons in a chemical bond
**draw arrowheads on trends sheet**
oxidation number – “+” or “-“ number which indicates how many electrons will be gained (-) or lost (+) when an atom forms a compound

8. Periodic Trends Illustrated
Draw the arrows on your chart and label

9. Review Watch the Video on the periodic table.
You must be at school. The video is on the N-All user drive if this link does not work.