1. 17.3: The Periodic Table

2. Traditionally, early Greeks considered that there were four classical elements: earth, air, fire, and water. Some Early Ideas About Elements

3.  Later, around 1667, it was thought there was the existence of, in addition to the classical four elements of the Greeks, an additional fire-like element called “” that was contained within combustible (burnable) or rustable bodies, and released during combustion or rusting.  Later, around 1667, it was thought there was the existence of, in addition to the classical four elements of the Greeks, an additional fire-like element called “phlogiston” that was contained within combustible (burnable) or rustable bodies, and released during combustion or rusting.  The theory was an attempt to explain oxidation processes such as combustion and the rusting of metals. Some Early Ideas About Elements

4.   The phlogiston theory from 1667 viewed phlogiston as a component of matter.  The burning or rusting of a material was considered to be the escaping of phlogiston from the matter.  If a material did not burn or rust, it was considered to contain no phlogiston. What the heck is “phlogiston?”

5.   In the late 1700s, Antoine Lavoisier of France suggested that burning was actually a chemical combination with oxygen.   Lavoisier realized that there needed to be a new concept of elements, compounds, and chemical change. Discovery of Modern Elements

6. What we now know... at least, for now.  We now know that there are 89 naturally- occurring elements and at least 23 short-lived and artificially prepared elements.  The elements of the periodic table are believed to be all the elements that exist in the universe!  Click here to see how we know: http://spiff.rit.edu/classes/phys301/lectures /spectra/spec_proper_orientation.gif http://spiff.rit.edu/classes/phys301/lectures /spectra/spec_proper_orientation.gif http://spiff.rit.edu/classes/phys301/lectures /spectra/spec_proper_orientation.gif

7.  The first 103 elements have internationally accepted names, which can come from:  an unusual or identifying property of the element.  places, cities, and countries.  famous scientists.  Greek mythology.  Astronomical objects. Naming the Elements

8.  The elements of aluminum, Iron, Oxygen, and Silicon make up about 88 percent of the earth's solid surface.  Water on the surface and in the air as clouds and fog is made up of hydrogen and oxygen.  The air is 99 percent nitrogen and oxygen.  Hydrogen, oxygen, and carbon make up 97 percent of a person.  Thus almost everything you see in this picture is made up of just seven elements.

9.  Dmitri Mendeleev was born in 1834 in Siberia, the youngest of 14 children, and he died in 1907.  He gave us a functional scheme with which to classify elements. Along Came Mendeleev...

10. Dmitri Mendeleev: Father of the Periodic Table  HOW HIS WORKED…  Put elements in rows by increasing atomic mass.  Put elements in columns by the way they reacted.  He was able to predict properties of undiscovered elements.  SOME PROBLEMS…  He had to leave blank spaces for what he said were undiscovered elements. (Turned out he was right!)  He broke the pattern of increasing atomic weight to keep similar reacting elements together.

11. Mendeleev’s Periodic Table  Scientists have since discovered the missing elements and found that their properties were close to what Mendeleev had predicted.  On March 6, 1869, he presented his periodic table to the scientific community.

12. Improvements  Mendeleev wasn’t too far off.  In 1913, Henry Moseley of England put elements in rows by increasing ATOMIC NUMBER instead of increasing atomic mass!!  If you look at cobalt and nickel, even though cobalt has fewer protons, its average atomic mass is greater than nickel’s.  Seaborgium and bohrium are the same way.

13. Groups or Families  Groups are columns of the periodic table.  Columns are vertical, like columns that hold up a porch roof.  Elements in the same group have similar chemical and physical properties!! (Mendeleev did that on purpose.)  Families have the same number of valence electrons.  They will form the same kinds of ions (charged particles) and react similarly.

14.  Valence electrons are the electrons in the outside energy level of an atom. Valence Electrons Valence Electrons http://www.chemicalelements.com/index.html  They are responsible for the bonding of one atom to another.

15. Families on the Periodic Table  Families may be one column, or several columns put together.  Families often have names rather than numbers (just like some families have a common last name).  http://www.periodicvi deos.com/ http://www.periodicvi deos.com/ http://www.periodicvi deos.com/

16.   Another way to draw an atom model is with an electron dot diagram, or Lewis Structure.   They simply use the symbol of the element and the number of valence electrons that element has.   All atoms become stable when they bond with another so that their outside energy level becomes stable.   They become stable when they have eight valence electrons in their outside energy level.   Elements generally stop bonding with others when they have eight electrons in the outermost energy level. This is called the “Rule of Octet.” Electron Dot Diagrams

17.   Rows are also called periods, and they are horizontal.   The row an element is in tells you how many energy levels it has.   There are up to 7 energy levels. Rows on the Periodic Table

18. Forming Ions Sodium (Na ) Chlorine (Cl ) - +

19. Using Dot Diagrams to Show Bonding Cl Sodium has one valence electron. Chlorine has 7 valence electrons. When they bond, you can see how chlorine now has a stable outer shell. You also know sodium is now stable since it got rid of its single valence electron. [Na] + [ Cl ] - Na

21.   Elements on the upper right side of the periodic table—AND hydrogen—are nonmetals.   Elements on the left hand side—EXCEPT hydrogen—are metals.   That includes the rows at the very bottom.   A zigzag line separates the metals from the nonmetals.   Many of the elements touching the zigzag line are called metalloids. Regions on the Table

22.   Hydrogen is the most abundant element in the universe.   Hydrogen, along with helium, form the building blocks of the larger elements.   The largest of the elements (the ones with the most protons) are believed to be formed in supernovas and flung out into space.   Supernovas are stars that explode with a great deal of heat and energy.   Elements with an atomic number above 92, AND Pm (61), and Tc (43) are rare or nonexistent on Earth.   They have been detected using a telescope with a spectrometer. Elements in the Universe

24. Visible Spectra of Known Elements