AgendaReading for the night: EbolaVocabulary CheckLesson: Mendeleev HistoryOne Element at a time project

Organizing the Organizing the ElementsElements

Looking for Patterns in the ElementsLooking for Patterns in the Elements

Record the activities of a typical day:Record the activities of a typical day:Monday:Monday:Tuesday:Tuesday:Wednesday:Wednesday:Thursday:Thursday:Friday: Friday:

Notice any patternsNotice any patterns

Matter is made up of about 100 different Matter is made up of about 100 different elements that have a variety of propertieselements that have a variety of properties

These These elements like your daily activities follow elements like your daily activities follow a pattern.a pattern.

Mendeleev, the Detective1800’s scientists suspect the 1800’s scientists suspect the elements couldelements could be organized in useful be organized in useful way. way.

1869, Russian scientist,1869, Russian scientist, Dmitri Mendeleev, Dmitri Mendeleev, recognized a hiddenrecognized a hidden pattern in the elementspattern in the elements..

One of his first observations was that some elements have similar chemical and physical properties.

Examples:Fluorine and Chlorine, both gases that irritate your lungs

if you breathe them in.Silver and Copper are both shiny metals that gradually

tarnish if exposed to air.

Mendeleev believed that Mendeleev believed that these similarities were these similarities were important clues to the important clues to the pattern he was looking for. pattern he was looking for.

He wrote the facts about the He wrote the facts about the elements on paper cards.elements on paper cards.

He He wrote all the properties he wrote all the properties he knew about an element, knew about an element, including its melting point, including its melting point, density and color.density and color.

Mendeleev also Mendeleev also recorded two other important recorded two other important properties:properties:

atomic massatomic massbonding powerbonding power..

The atomic mass is the average mass of one The atomic mass is the average mass of one atom of an element.atom of an element.

~ Mendeleev found the atomic mass of elements from the elements comparison to hydrogen, the lightest of elements.

~ Bonding power refers to the number of chemical bonds an element can form.

~ This was determined by studying how each element formed compounds with oxygen.

First Periodic Table~ Mendeleev took his note cards and began to arrange them in ~ Mendeleev took his note cards and began to arrange them in

different patterns. different patterns. ~ He noticed that patterns appeared when the elements were ~ He noticed that patterns appeared when the elements were

arranged in order of increasing atomic mass. He noticed that arranged in order of increasing atomic mass. He noticed that the elements bonding power changed in an orderly way toothe elements bonding power changed in an orderly way too.

~ As Mendeleev discovered, arranging the elements by increasing atomic mass does not produce a perfect table.

~ He moved the cards to positions where they fit be.

~ By doing so this left 3 blank spaces. He boldly stated that these spaces would be filled in eventually because they had not yet been discovered.

~ 1869 Mendeleev published the first periodic table of ~ 1869 Mendeleev published the first periodic table of elements.elements.

~ Periodic means “regular repeating pattern”.~ Periodic means “regular repeating pattern”.

~ In the modern Periodic Table, the properties of the ~ In the modern Periodic Table, the properties of the elements repeat in each row – or period – of the table.elements repeat in each row – or period – of the table.

~ Within the next 16 years scientists found Mendeleev’s ~ Within the next 16 years scientists found Mendeleev’s missing elements. missing elements.

Homework1. Begin your project:

pick an element2. Research that

element: fill in the graphic organizer

3. Finish nightly reading and questions