Spark Please complete the last parts of the lab from yesterday. If your group hasn’t done it already, you will need to make the graph by hand and carefully determine the melting point of wax. Get me your data. Answer the analysis questions. Turn it in. CLEAN OUT YOUR TEST TUBES!!!!!!!!! 20 minutes or it will be late.

Group Midterm Review With your group decide who will be responsible for correcting those problems that your group attempted and missed. Midterm Corrections will be due next Monday on the test correction form. No exceptions this time.

Let’s meet some new friends… Rearrange yourself like atoms in a chemical reaction breaking old bonds and forming new ones. If you can, sit somewhere new.

The Periodic Table скажите пожалуйста, где туалет? Where is the bathroom, please? Let’s learn some Russian!

Spark Добрый день Мои друзья! – Good Afternoon my Friends! Review your answers to the prelab questions with your new groups http://youtu.be/EYOunr2Lwxs

Tips for Mendeleev’s Cards Read the directions. There are 3 parts. Keep the cards separate for each part until the directions call for them. Cut out the cards. Look for properties by which the cards can be grouped and place them in some type of order. Be able to defend your arrangement . Diagram your table and answer analysis questions. Hand in 1 per group.

Follow Up and Finish… Answer the analysis questions and hand in 1 set/group. Then… Ask yourselves the following questions: What criteria did you use to organize your table for part 1 of the activity? How useful would your table be if a new element was discovered or created? Where would it fit in your table? How would you know where to place it? DO THIS: Now place your cards in the same order as Mendeleev. Focus on the compounds property. Do you see a pattern?

Mendeleev and Germany's Lothar Meyer...handout In 1869, Russia's Dmitri Mendeleev and Germany's Lothar Meyer...handout Mendeleev Meyer

published nearly identical classification tables for the 63 elements known at the time... Mendeleev Meyer

based on recurring chemical and physical properties when elements were arranged... Mendeleev Meyer

in order of increasing atomic weight. Mendeleev Meyer

Although their observations were identical, Mendeleev is given the credit because he predicted the existence of undiscovered elements and left spaces for them. Mendeleev

Copy Cat Quickly arrange your cards like Mendeleev did in his table and look for the pattern. See how the table reflects atomic number and the compounds formed by the element How often (what interval) does the pattern repeat itself?

Mendeleev grouped elements Into families by their valence Or combining power Na = 1 Ca = 2 Al = 3 C = 4 N = 3 O = 2 Cl = 1 Elements in the same groups have the same combining powers Na = 1 O = 2 For sodium oxide the ratio of sodium to oxygen is 2:1 Mendeleev

Mendeleev's table, published in the journal Annalen der Chemie in 1871.

Mendeleev is known as the Father of the Periodic Table. And almost no one outside of Germany knows about Meyer.

Dobereiner’s Triads

Hmmm… A new element: It’s a shiny blue liquid, that turns into a gas at room temperature has a mass of 3.5 and forms a compound with chlorine in a 1:3 ratio. Where on the periodic table should it be placed?

In 1913, Henry Moseley developed the concept of atomic numbers.

Moseley correctly said that the atomic number was equal to the number of protons in the nucleus...

AND the number of electrons in the atom.

“Whoa, whoa, whoa, Mr. F!” “What in the heck are protons and electrons?” -Bronson Holland, science enthusiast A brief review for those of us who do not “hablo atomos”

Who are these white guys? In this lesson, we’ll learn about the men whose quests for knowledge about the fundamental nature of the universe helped define our views.

Atomos The atomic model has changed throughout the centuries, starting in 400 BC, when it looked like a billiard ball →

Democritus 400 BC This is the Greek philosopher Democritus who began the search for a description of matter more than 2400 years ago. He asked: Could matter be divided into smaller and smaller pieces forever, or was there a limit to the number of times a piece of matter could be divided?

Atomos His theory: Matter could not be divided into smaller and smaller pieces forever, eventually the smallest possible piece would be obtained. This piece would be indivisible. He named the smallest piece of matter “atomos,” meaning “not to be cut.”

Atomos To Democritus, atoms were small, hard particles that were all made of the same material but were different shapes and sizes. Atoms were infinite in number, always moving and capable of joining together.

Way to go Western Civilization! This theory was ignored and forgotten for more than 2000 years! Way to go Western Civilization!

Why? The eminent philosophers of the time, Aristotle and Plato, had a more respected, (and ultimately wrong) theory. Aristotle and Plato favored the earth, fire, air and water approach to the nature of matter. Their ideas held sway because of their eminence as philosophers. The atomos idea was buried for approximately 2000 years.

Alchemy!

Dalton’s Model In the early 1800s, the English Chemist John Dalton performed a number of experiments that eventually led to the acceptance of the idea of atoms.

John Dalton’s Elements

Dalton’s Theory He deduced that all elements are composed of atoms. Atoms are indivisible and indestructible particles. Atoms of the same element are exactly alike. Atoms of different elements are different. Compounds are formed by the joining of atoms of two or more elements.

This theory became one of the foundations of modern chemistry. We now believe atoms are composed of protons and neutrons in the nucleus (the center) and electrons around the outside of the atom. p+ + no = Atomic Mass p+ = e- (electric charge cancels out) = atomic number If an electron had a mass equal to a bag of Doritos, a proton would have a mass of a compact car. If the nucleus was a dime on the 50 yard line of a stadium, the electrons would be the bleachers with empty space in between

When Moseley arranged atoms by their increasing atomic number, the few problems with Mendeleev's table disappeared.

In 1945, Glenn Seaborg proposed pulling the lanthanide and actinide series out of the main body of elements on the table.

1954 Seaborg