Find the Missing Alien 1. Study the 17 pictures of aliens. 2. Organize the pictures based on patterns. 3. Identify and draw the missing alien.

The Periodic Table  Development of the Periodic Table  Organization of the Periodic Table  Periodic Trends

Almost everything you see in this picture is made up of just 7 elements. H, O, N, C, Si, Al, Fe

Elements  Elements cannot be broken down by ordinary chemical processes.  118 known elements 94 occur naturally 24 man-made

A. Development of the Periodic Table  Dmitri Mendeleev (1869) Organized elements by increasing atomic mass. Grouped elements with similar chemical and physical properties Predicted the existence of undiscovered elements.

A. Development of the Periodic Table  Henry Mosely (1913) Organized elements by increasing atomic number.  Glen Seaborg (1940) Discovered transuranium elements from Reordered actinide/lanthanide series

B. Organization – Metallic Character  Metals  Nonmetals  Metalloids

Properties of Metals and Nonmetals Metals: -All are solids at room temperature (except Hg) -Malleable and ductile -Lustrous -Conduct heat and electricity -Typically lose electrons when they undergo reactions Nonmetals: -Usually brittle solids or gases at room temperature (except Br) -Not malleable and ductile -Non-lustrous -Poor conductors -Typically gain electrons when they undergo reactions

Properties of Metalloids Have properties of both metals and nonmetals: - May be shiny or dull - Shape is easily changed - Typically conduct heat and electricity better than nonmetals but not as well as metals - Often used as semiconductors

B. Organization – Columns & Rows  Group (Family)  Period

B. Organization – Families  Alkali Metals  Alkaline Earth Metals  Transition Metals  Halogens  Noble Gases

Periodic Table and Electron Configurations

B. Organization - Sections Lanthanides - part of period 6 Actinides - part of period 7 Overall Electron Configuration

Period (row) Each period roughly corresponds to layer of electrons at a specific energy level Each period begins with a new outer electron orbital Each period ends with a completely filled outer orbital that has the maximum number of electrons for that orbital.

Families (columns) Elements in the same family have the same number of electrons in its outermost shell Elements within a family have similar properties

 Periodic Law Properties of elements repeat periodically when the elements are arranged by increasing atomic number. C. Periodic Trends

C. Periodic Trend – Atomic Radius  Atomic Radius ½ the distance between bonded nuclei “size of the atom” Depends on how far the outermost valence electrons are from the nucleus d

 Atomic Radius Increases to the LEFT and DOWN C. Periodic Trends – Atomic Radius

 Atomic radius decreases with increasing atomic number across a period. Increased nuclear charge (+) pulls electrons (-) within same energy level in more tightly. C. Periodic Trends – Atomic Radius

 Atomic radius increases down a family Electrons at higher energy levels have larger orbitals Shielding - core electrons block the attraction between the nucleus and the valence electrons C. Periodic Trends – Atomic Radius

 Which atom has the larger radius? BeorBa CaorBr Ba Ca

 First Ionization Energy Energy required to remove the highest energy electron from a neutral atom. © 1998 LOGAL C. Periodic Trends – Ionization Energy

 First Ionization Energy C. Periodic Trends – Ionization Energy K Na Li Ar Ne He

 First ionization energy decreases down a family. The highest energy electrons are farther from the nucleus and loosely held.  First ionization energy increases across a period. Electrons experience increasing nuclear charge with little shielding and are held more tightly to the nucleus. C. Periodic Trend – Ionization Energy

C. Periodic Trends – Ionization Energy  Which atom has the higher first I.E.? NorBi BaorNe N Ne

C. Periodic Trends – Ionization Energy  First Ionization Energy Increases to the RIGHT and UP.

C. Periodic Trend – Electro negativity  Electro negativity: a relative measure of the tendency of an atom to attract electrons toward itself in a chemical bond.  The more higher the electro negativity value, the more strongly an atom pulls electrons toward it.

C. Periodic Trend – Electro negativity Electro negativity Increases to the right and up

C. Periodic Trend – Electro negativity  Electro negativity increases from left to right across a period. As the nuclear charge increases and the atomic radius decreases, the increased attraction makes it easier for atoms to attract the electron.  Electron negativity decreases as you go down the group due to increasing atomic radius.

B. Organization – Families  Alkali Metals  Alkaline Earth Metals  Transition Metals  Halogens  Noble Gases

Reactivity of Families  Reactivity of families Alkali Metals – most reactive Halogens – 2nd Alkaline earth metals – 3 rd Noble gases – least reactive  Reactivity increases with atomic number within a family

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