Periodic Table and Periodicity Chapter 14 Periodic Table and Periodicity

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. http://www.chemheritage.org/EducationalServices/chemach/ppt/lm04.html

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

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”

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

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

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 http://intro.chem.okstate.edu/WorkshopFolder/Ionicradii.html

Periodic Trends Illustrated Draw the arrows on your chart and label

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.