Learning Target: Classify elements according to their location on the Periodic Table

 Identify the following as being an alkalai metal, alkaline earth metal, transition metal, semi-conductor, halogen, or noble gas:  Germanium  Tungsten  Potassium  Radon  Strontium  Uranium  Silicon  Beryllium  Palladium

 Which of the following are main-group elements?  Magnesium  Vanadium  Antimony  Lead  Neptunium  Cesium  Rutherfordium  Boron  Indium

Section 1: Who’s Who??? Learning Target: Explain the development of Periodic Law

 1817 – Dobereiner Grouped elements in TRIADS… Three elements with similar properties  1865 – Newlands Arranged by increasing atomic MASS. Law of Octaves = Similar properties over EIGHT elements

 1870 – Mendeleev Created an 8 Column table based on ATOMIC MASS Elements with similar properties were in the same column

Problems w/ Mendeleev’s table: 1. Some elements did not fit the order. Ex: Tellurium (Te) and Iodine (I) 2. There were gaps in the table BUT he was able to predict the properties and masses of the unknown elements very accurately.

 1913 – Mosley Studied X-ray spectra of elements and noticed they correlated with atomic number Arranged elements with increasing ATOMIC NUMBER  PERIODIC LAW: Properties of the elements are a (periodic) function of their atomic number

 1944 –Glenn Seaborg  Last rearrangement of the periodic table – created the actinide series

Dobereiner Triads Newlands Law of Octaves Mendeleev First 8 column table Mosley Periodic Law Seaborg Actinide Series

Section 2

 Atomic properties are determined by ELECTRON CONFIGURATION.  Ex. 1s 2 2s 2 2p 6 3s 2 3p 3  Therefore…the table is designed on the basis of electron configuration…

 Valence Electrons: Electrons that are found in an atom’s outer most shell  Determines chemical properties of an atom  These are the electrons that can be gained, lost or shared when forming compounds

 OCTET RULE… 8 electrons in the outer energy level renders an atom UNREACTIVE Unreactive = Very Stable So…which elements are considered unreactive?

A: The Noble Gases

 Atoms react with other atoms so all atoms end up with FULL OUTER ENERGY LEVELS (i.e. compounds) 1. They may add electrons 2. They may lose electrons 3. They may share electrons

Section 3 Learning Target: Identify properties of metals, nonmetals and metalloids

 Don’t forget your color-coded periodic table…  It identifies the… Groups Periods Main Group Elements

 It also classifies elements as… Metals:  Alkali metals  Alkaline Earth metals  Transition metals  Lanthanide Series  Actinide Series  Other Metals Nonmetals:  Noble gases  Halogens  Other nonmetals Metalloids:  semiconductors

 Metals –On the LEFT of the stairs  Nonmetals – On the RIGHT of the stairs  Metalloids – Attached to stairs (not shown here)

METALSNONMETALS 1. Typically Solids1. Gasses or BRITTLE solids 2. Shiny2. Dull 3. Conduct Heat and Electricity 3. Insulators 4.Tendency when forming compounds to lose outer electrons 4.Tendency when forming compounds to GAIN or SHARE electrons

RULE of THUMB  Metals: 3 or fewer outer energy level electrons  Nonmetals: 5 or more outer energy level electrons  Metalloids: Properties of both Metals and Nonmetals Semiconductors

Section 4 Learning Target: Describe element trends on the Periodic Table

 What is a trend?  A predictable change in a particular direction  (FOCUS ON MAIN GROUP ELEMENTS)

Atomic Radii  ½ the distance between the nuclei of identical atoms that are bonded together  Atomic Radii increase from top to bottom and from right to left on the periodic table Radius = d/2

Periodic Table Increases

 Increases as you move down due to electron shielding electrons in the inner energy levels are between the nucleus and the outer electrons and therefore are shielded from being pulled away

 Decrease as you go right due to increasing charge of the nucleus (means increases as you go left due to decreasing charge of nucleus) although more electrons are also present they are at the same distance from the nucleus b/c they are in the same energy level

 Gallium  Yttrium  Helium  Hafnium  Thallium  Strontium  Neon  Vanadium

Ions  Atom or group of atoms that has a positive or negative charge Positive charge occurs when atom loses electrons Ex: Na + : Sodium that has lost an electron, and now has 10 e - Negative charge occurs when atom gains electrons Ex: Cl - : Chlorine that has gained an electron, and now has 18 e -  This process that results in an ion requires energy—this process is referred to as ionization

Ionization Energy  Energy required to remove one electron from a neutral atom of an element This happens when compounds form  Ionization energy tends to increase from bottom to top and left to right

Periodic Table Increases

 As you move across, the nucleus gets larger and holds the electrons more tightly THEREFORE harder to remove  Requires MORE energy (higher ionization energy)

 As you move down, the outer most electrons are farther away from the nucleus THEREFORE easier to remove  Requires LESS energy (lower ionization energy)

 Iron  Cesium  Sulfur  Iodine  Cobalt  Rhenium  Tin  Bismuth

Electron Affinity  Energy change that occurs when an electron is acquired by a neutral atom (The ability to attract and hold an electron.)  Electron affinity follows the same trend as Ionization Energy (Bottom to Top/Left to Right generally more exothermic)

Periodic Table Increases

 Gold  Platinum  Barium  Fluorine  Osmium  Cadmium  Beryllium  Aluminum