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- combine vigorously with many nonmetals very reactive, not found in nature as free elements. (Video)

• Group 2- Alkaline-Earth Metals- they are harder, denser, stronger, and have higher melting points than group 1

• not found in nature as free elements.

• Groups 3-12- Transition metals they have metallic properties.

Iron

Copper

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 nonmetals they form “salts”

• Group 18- Noble Gases- Least reactive family. WHY????

F-Block • Lanthanides- “rare

earths” all shiny reactive metals.

• Actinides- all unstable and radioactive. 1st 4 found naturally all the rest are lab-made.

Cerium

5-3 Electron configuration and Periodic Properties

• Atomic Radius- is one-half the distance between the nuclei of identical atoms joined in a molecule.

Small

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-

Atom of Na

11 protons 11 electrons

Ion of Sodium (Na+)

11 protons 10 electrons

Atom of Cl

17 protons 17 electrons

Ion of Chlorine (Cl-)

17 protons 18 electrons

One e- added

• 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

CATIONS

ANIONS

• 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.org/chemlectures/menu.html

• “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.edu/physics/2000/periodic_table/periodic_properties.html

• “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.