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

• 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

Group 1: Alkali Metals

• very reactive• never found free in

nature• react readily with

water• shiny, light in weight

Li Na

K Rb

Cs Frno images of

Francium available

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• Metal• Nonmetal• Metal

Review

• Pick two elements that have properties similar to those of the element calcium

• Zn• Mg • Cr• Sr