Chapter #5 The Periodic Law

5-1 History of the Periodic Table Cannizzaro (1826-1910) developed a method for measuring atomic masses and interpreting the results of the measurements. Stanislao Cannizzaro

Mendeleev (1834-1907) Created the 1st periodic table by increasing atomic mass. Dmitri Mendeleev

Moseley (1887-1915) set up the periodic table according to increasing atomic number. Henry Moseley

The word "periodic" means that there is a repeating pattern. Examples of things that are periodic are, days of the week, the months of the year, the seasons, etc.. In regards to the periodic table of elements, periodic refers to the properties of the elements that repeat with each row (period) of the table.

The modern periodic law states: The chemical and physical properties of the elements are periodic functions of their atomic numbers. Put in other words, when the elements are arranged in order of increasing atomic number, there is a periodic repetition of their properties.

The periodic table is an arrangement of the elements in order of their atomic numbers so that elements with similar properties fall in the same family (group).

5-2 Electron Configuration and the Periodic Table Families 1 & 2 = s-block Families 3-12= d- block Families 13-18= p-block Lanthanide and Actinide series= f-block

Group (Family) 1- Alkali Metals- Most reactive metals.

Group 2- Alkaline-Earth Metals- Less reactive than group 1.

Groups 3-12- Transition metals they have metallic properties. Copper Iron Groups 3-12- Transition metals they have metallic properties. Cobalt Chromium

Main-group elements are the p-block and s-block elements. Group 13- Boron's Family Group 14- Carbon’s Family Group 15- Nitrogen's Family Group 16- Oxygen’s Family Group 17- Halogens the most reactive elements they form “salts” Group 18- Noble Gases- Not reactive . WHY????

F-Block Lanthanides- “rare earths” 58-71 Actinides- 90-103 Cerium

5-3 Electron configuration and Periodic Properties Small Atomic Radius- is one-half the distance between the nuclei of identical atoms joined in a molecule. BIG

Ionization Energy-the energy required to remove 1 e- from an atom of an element (lose electrons) Ion- is an atom or group of atoms that have a charge (+ or -).

Electron Affinity- is the energy change that occurs when a electron is acquired by a neutral atom (gain e-).

Ions Cation- positive ion Anion- negative ion One electron is removed Positive because e- Ion of Sodium (Na+) 11 protons 10 electrons Atom of Na 11 protons 11 electrons One e- added Atom of Cl 17 protons 17 electrons Ion of Chlorine (Cl-) 17 protons 18 electrons

Valence e- (outer most) the e- available to be lost, gained, or shared in the formation of chemical compounds. Groups 13-18 Val e- = group # - 10 ANIONS CATIONS

Electronegativity:  relative tendency of an atom to attract electrons to itself when it is bonded to another atom. *It follows the same trend as electron affinity and ionization energy.  It increases across a period and up a group. *The most active metals (lower left) have lowest electronegativities.  Francium has the lowest electronegativity. *Non-metals (upper right) have the highest electronegativities.  *Flourine has the highest electronegativity of all                other elements.

Work Cited “Ion Cartoon”. Drawing. Aug. 8, 2006. http://ccmm.fc.ul.pt/vnunes/ensino/quimica2.htm “Canizzaro”. Photo. Aug. 8, 2006. http://www.unipa.it/~cheminor/ “Mendeleev”. Photo. Aug. 8, 2006. http://academic.brooklyn.cuny.edu/chem/howell/chem11/octetSet1.htm “Moseley”. Photo. Aug. 8, 2006. http://home.iitk.ac.in/~sreerup/bso203/Moseley.jpg “Mendeleev Table and history of the periodic table”. Photo. Aug. 8, 2006. http://www.batesville.k12.in.us/bms/Staff/smithhomepage/webquests/Mendeleevtable.gif “Periodic Table”. Gif. Aug. 8, 2006. http://imagine.gsfc.nasa.gov/docs/features/topics/instrument_design/periodic.gif

“Blocks of the Periodic table”. Diagram. Aug. 8, 2006. http://boomeria “Sodium Pictures”. Picture. Aug. 8, 2006. http://www.theodoregray.com/PeriodicTable/Stories/011.2/ “Magnesium”. Picture. Aug. 8, 2006. http://www.theodoregray.com/PeriodicTable/Elements/012/index.s7.html “Transition metal pictures”. Photo. Aug. 8, 2006. http://www.theodoregray.com/PeriodicTable/Elements/TransitionMetals/index.s7.html “F-Block elements”. Photo. Aug. 8, 2006. http://www.theodoregray.com/PeriodicTable/Elements/095/index.s7.html “Periodic Table of Elements”. Chart. Aug. 9, 2006. http://users.erols.com/kdennis/periodictable.jpg

“Atomic Radii Chart”. Diagram. Aug. 8, 2006. http://www. colorado “Electron Affinity Chart”. Diagram. Aug. 8, 2006. http://www.chemistry.ohio-state.edu/~grandinetti/teaching/Chem121/lectures/periodic%20trends/affinity.html “Electronegativity chart and information”. Diagram. Aug. 9, 2006. http://www.homewood.k12.al.us/~kreaves/Chemicalbonding.htm “Ionization energy chart”. Diagram. Aug. 9, 2006. http://neon.mems.cmu.edu/27201/ionization-enthalpy-1-c.gif “Sodium and Chlorine ions”. Aug. 9, 2006. http://www.dgpc.ulaval.ca/bio90192/chap1/ions.htm Holt, Rinehart and Winston. Modern Chemistry. Harcourt Brace & Company. 1999.