Mendeleev Arranged the 70 known elements at the time in columns in order of increasing atomic mass. He then arranged the columns so that the elements with the most similarities were side by side. Created the first Periodic Table.

Mendeleev’s First Periodic Table

Periodic Table: an arrangement of the elements according to the similarities in their properties Mendeleev was even able to predict the physical and chemical properties of the missing elements. (When these elements were discovered, they were found to have properties similar to those predicted)

Moseley Moseley later arranged the elements in a table by order of atomic number instead of atomic mass

The Periodic Table Periods: horizontal rows are called periods There are seven periods The properties within a period change as you move across it from element to element If you move from one period to the next, the properties within the period repeat All elements in a period have the same # of atomic orbitals Ex. First period (1 orbital) Second period (2 orbitals)

The Periodic Table Groups or Families: Vertical columns of elements in the PT The elements in any family of the PT have similar physical and chemical properties Have the same number of electrons in their outer orbitals (valence electrons) Hydrogen has characteristics of both group 1 and 7 Helium needs only two electrons in its outer shell to be filled (happy). Families have specific names associated with them because they have similar physical and chemical properties

75% of Elements are Classified as Metals Properties of metals: conduct electricity high luster ductile (able to be drawn into wires) malleable (able to be beaten into thin sheets elements on the left and center of the PT are metals

Groups or Families: divided into 8 groups

no images of Francium available Group 1: Alkali Metals Li very reactive never found free in nature react readily with water shiny, light in weight Na K Rb Fr no images of Francium available Cs

Group 2: Alkaline Earth Metals reacts with oxygen not as reactive as Group 1, makes bonds very easily Ca Calcium

Group 3: Boron group, made of metals and metalloids Group 4: Carbon group, made of Metals and Nonmetals Group 5: Nitrogen group, elements form an oxygen or sulfur compound Group 6: Oxygen group, Nonmetals

Group 7: Halogens elements combine violently with alkali metals to form salts Halogens mean “salt-forming” Highly reactive 7 electrons in outer shell, only need one to be happy

Group 8: Noble Gases have full outer shells with 8 electrons (except for He) least reactive group not very abundant Neon in advertisement signs Argon light bulbs Helium balloons Xenon used in headlamps (ultra bright-blue)

Metalloids: Stair step line that distinguishes metals from non-metals. Drawn from between Boron & Aluminum to the border of Polonium & Astatine Boron Silicon Germanium Arsenic Antimony Tellurium Polonium

Transition Metals: All elements between Group 2 and Group 3, including the inner transition metals (lanthanide & actinide series) Able to put more than 8 electrons in their next to last shell Can use the two outermost orbitals to bond with other elements Actinide series are radioactive and some cannot be found in nature Lanthanide series can be found naturally on earth

Transition Metals

Periodic Table Review What criteria did Mendeleev use to construct his PT? arranged elements by order of atomic number arranged elements by order of atomic mass What criteria did Moseley use to reconstruct the PT? arranged elements by order of atomic number arranged elements by order of atomic mass

Review A period on the Periodic Table: is represented by vertical columns of elements which have similar physical properties and chemical properties is represented by horizontal rows of elements and the properties of the elements change as you move from element to element

Review A Family/Group on the Periodic Table: is represented by vertical columns of elements which have similar physical properties and chemical properties is represented by horizontal rows of elements and the properties of the elements change as you move from element to element

Review Identify each element as a metal, metalloid, or nonmetal gold silicon manganese sulfur barium Metal Metalloid Nonmetal

Review Pick two elements that have properties similar to those of the element calcium Zn Mg Cr Sr