The Periodic TableThe Periodic Table Courtesy of Periodic Table of the Elements v. 4.0Courtesy of Periodic Table of the Elements v. 4.0

by Kostas Tsigaridis by Kostas Tsigaridis (http://ptoe.move.to/)

Johann DobereinerJohann Dobereiner

1780 - 1849

Model of triads

•In 1829, elements into groups of 3• triads.• similar chemical properties and physical properties.

(ex. Cl, Br, I andCa, Sr, Ba)

John NewlandsJohn Newlands

1838 - 1898

Law of Octaves

-In 1863, arranged in “octaves” -(after arranging in order of increasing atomic mass) =certain properties repeated every 8th element. Why? !!!!!

REVIEW

1. Dobereiner arranged elements into groups called THE MODEL of _________?2. Why were there only 3 elements in each group?3. The Law of Octaves developed by _______ _________, worked well at the time because of which rule we know today?

Dmitri Mendeleev Dmitri Mendeleev is called the is called the Father of the Periodic TableFather of the Periodic Table

1834-19071834-1907 Chemistry Professor Chemistry Professor

at St. Petersburg at St. Petersburg UniversityUniversity

He wrote a textbookHe wrote a textbook Principles of Chemistry and and organized elements organized elements by by similar propertiessimilar properties

In In 18691869 ,Based upon ,Based upon patterns he noticed patterns he noticed when relating when relating atomic atomic mass, physical & mass, physical & chemical propertieschemical properties, he , he developed a Periodic developed a Periodic Table of 63 elementsTable of 63 elements

VVERY ERY GGOOD OOD HHOT OT PPIES IES (Vertical Groups / Horizontal (Vertical Groups / Horizontal Periods)Periods)

He predicted 3 unknown He predicted 3 unknown elements and their elements and their properties (germamium, properties (germamium, scandium, and gallium).scandium, and gallium).

Lothar MeyerLothar Meyer

At the At the same timesame time, , 18691869, Meyer , Meyer published his own published his own table of the table of the elements elements organized by organized by increasing increasing atomic atomic mass.mass.

1830 - 18951830 - 1895

Review:Review: 1. Dmitri Mendeleev put his periodic 1. Dmitri Mendeleev put his periodic

table in order of increasing_____ _____?table in order of increasing_____ _____? 2. Mendeleev noticed that when the 2. Mendeleev noticed that when the

elements were in order of increasing elements were in order of increasing _____ ____ , their chemical/physical _____ ____ , their chemical/physical properties __________.properties __________.

3.What does VERY GOOD HOT PIES 3.What does VERY GOOD HOT PIES stand for?stand for?

How did Meyer arrange his Periodic How did Meyer arrange his Periodic Table? Table?

Both Mendeleev Both Mendeleev and Meyer and Meyer arranged the arranged the elements in order elements in order of of increasing increasing atomic mass.atomic mass.

Both left vacant Both left vacant spaces where spaces where unknown unknown elements should elements should fit.fit.

So why is So why is Mendeleev Mendeleev called the called the “father of the “father of the modern periodic modern periodic table” and not table” and not Meyer, or both?Meyer, or both?

Mendeleev… Mendeleev…

• stated that if the stated that if the atomic weight atomic weight of an of an element caused it to be placed in the element caused it to be placed in the wrong group, then the wrong group, then the weight must be weight must be wrongwrong. (He corrected the atomic masses . (He corrected the atomic masses of Be, In, and U)of Be, In, and U)

• was so confident in his table that he used it was so confident in his table that he used it to predict the to predict the physical properties physical properties of three of three elements that were yet unknown.elements that were yet unknown.

After the discovery of these unknown After the discovery of these unknown elements between 1874 and 1885, elements between 1874 and 1885, and the fact that Mendeleev’s and the fact that Mendeleev’s predictions for Sc, Ga, and Ge were predictions for Sc, Ga, and Ge were amazingly close amazingly close to the actual values, to the actual values, his table was generally accepted!his table was generally accepted!

Henry Moseley Henry Moseley (1887-1915) (1887-1915) In 1913, In 1913, through his work with through his work with X-rays, he X-rays, he determined the determined the actual nuclear actual nuclear charge (atomic charge (atomic number) of the number) of the elements*. In 1913, elements*. In 1913, he rearranged the he rearranged the elements in order of elements in order of increasing atomic increasing atomic number.number.

Henry Moseley

Interest FACT…..Interest FACT…..

Moseley’s Moseley’s research was halted when research was halted when the British government sent him to the British government sent him to serve as a foot soldier in WWI. He was serve as a foot soldier in WWI. He was killed in the fighting in Gallipoli by a killed in the fighting in Gallipoli by a sniper’s bullet, at the age of 28. sniper’s bullet, at the age of 28. Because of this loss, the British Because of this loss, the British government later restricted its government later restricted its scientists to noncombatant duties scientists to noncombatant duties during WWII.during WWII.

REVIEW:REVIEW: 1. 1. Henry Moseley Henry Moseley put his periodic put his periodic

table in order of increasing ______ table in order of increasing ______ _______?_______?

2.What can you infer about elements 2.What can you infer about elements in the same group?in the same group?

Who is considered the FATHER of the Who is considered the FATHER of the PERIODIC TABLE? PERIODIC TABLE?

Glenn SeaborgGlenn Seaborg, 1912- 1999, was a Chemistry , 1912- 1999, was a Chemistry professor at the University of California at Berkeleyprofessor at the University of California at Berkeley

He was the first to propose rearranging the Table by adding He was the first to propose rearranging the Table by adding the Actinide Seriesthe Actinide Series

He discovered and isolated 10 transuranic elements He discovered and isolated 10 transuranic elements (plutonium, americium, curium, berkelium, californium, (plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium and einsteinium, fermium, mendelevium, nobelium and seaborgium) seaborgium)

REVIEW:REVIEW: 1. ___________ was the first to 1. ___________ was the first to

propose rearranging the Table by propose rearranging the Table by adding the ___________ ________.adding the ___________ ________.

2.What is the atomic number of the 2.What is the atomic number of the element named after Seaborg? (the element named after Seaborg? (the only person to have an element only person to have an element named after them while living.)named after them while living.)