Friday, Nov. 22nd: “A” DayMonday, Nov. 25th: “B” Day

AgendaCollect Popcorn Lab/Chapter3 Tests: “Atoms & Moles”Movie: “Electron Configuration and the Periodic Table”Begin Chapter 4: The Periodic Table

Sec. 4.1: “How Are Elements Organized?” In-Class/Homework:

Section 4.1 review, pg. 122: #1-13 “What is the Periodic Table?” WorksheetFinish movie worksheet

Homework: Concept Review: “How Are Elements Organized?”

Popcorn LabReflection Statement

1. Was your hypothesis correct?2. What were some possible sources of error in

this lab?3. How could you minimize these errors in

future trials?4. Did this lab help you understand how the law

of conservation of mass could be used?

Chapter 3 Tests“Atoms and Moles”

Class Average Grade (out of 70)

Average Percentage

2A 53.83 76.90%

4A 58.68 83.83%

1B 62.44 89.20%

3B 64.65 92.36%

Movie:“Electron Configuration and the Periodic

Table”Complete the blank periodic table worksheet

along with Mr. Sweatervest as he discusses electron configurations and the periodic table.

The completed periodic table worksheet will be due next time.

Extra credit: keep track of how many times Mr. Sweatervest thinks electron configurations are “interesting”.

Chapter 4: The Periodic Table

Patterns in Element PropertiesThe Periodic Law

This guy is almost as handsome asMr. Sweatervest!

John Newlands Noticed a Periodic Pattern

In 1865, English chemist John Newlands arranged the known elements according to their properties and in order of increasing atomic mass.

Newlands noticed that all of the elements in a given row had similar chemical and physical properties and these properties repeated every 8 elements.

Newlands called this pattern the law of octaves.

Dmitri Mendeleev Invented the First Periodic Table

In 1869, Russian chemist Dmitri Mendeleev made the first periodic table with all of the 63 elements known at that time.

He wrote the chemical symbol, name, chemical/physical properties, and atomic mass on cards.

He arranged the cards in order of increasing atomic mass.

Dmitri Mendeleev Invented the First Periodic Table

Mendeleev started a new row whenever he noticed the chemical properties of the elements were repeating.

He left gaps in his table for elements that weren’t discovered yet.

Problem: The elements didn’t always fit neatly in order of increasing atomic mass. (Examples: Te and I)

Henry MoseleyAbout 40 years after Mendeleev’s published

periodic table, English chemist Henry Moseley found a different physical basis for the arrangement of elements.

He arranged them by increasing atomic number and the discrepancies in Mendeleev’s table disappeared.

The Periodic Law

Periodic Law: the law that states that the repeating physical and chemical properties of elements change periodically with their atomic number.

Organization of the Periodic TableIf you look at the blank periodic table you filled

out while watching the last Mr. Sweatervest video, you’ll see that each vertical column of elements in the periodic table have the same number of electrons in their outer energy level.

These electrons are called valence electrons.

Valence electron: an electron found in the outermost level of an atom that determines the atom’s chemical properties.

Organization of the Periodic TableGroup/Family: a vertical column of elements in

the periodic table; elements in a group share similar chemical properties.

Period: a horizontal row of elements in the periodic table; elements in a period have the same number of occupied energy levels.

GROUP

P E R I O D

In-Class/Homework

Section 4.1 Review, pg. 122: #1-13“What is the Periodic Table?” WorksheetFinish movie worksheet

Homework:Concept Review: “How are Elements Organized?”

*Quiz over section 4.1 next time*