Tuesday, September 18- TEST DAY Turn in your Ch. 3 /4 Study Guide to the metal shelf (make sure NAME on it!) Take out a sheet of paper, write name, date, and title “Chapter ¾ Exam” You will need a calculator and periodic table When you finish, begin completing Chapter 5 Vocab.
Wednesday, September 19 Do not write down: 1. How many significant figures are in ? 2. What is the scientific notation for ? 3. What is the scientific notation of ?
Chapter 3: 1-10 Chapter 4: Graphic Organizer: Using the vocabulary words posted on the wall, you and your partner (s) are to create a graphic organizer to summarize and show the relationship between the terms in Chapter 3 and 4
Thursday, September 20 Take out one piece of paper, title it “Periodic Law” 1. What is the purpose of the periodic table? 2. What model did Bohr suggest?
Friday, September 21 Pick up one Chemistry Textbook Take out your notes from yesterday (with the table)
Periodic Table: What’s the trend? Think about your closet or music collection. How do you organize your possessions?
Bohr Model Niels BohrNiels Bohr in 1913, depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus—similar in structure to the solar system, but with electrostatic forces providing attraction, rather than gravity.atomnucleus electronssolar systemelectrostatic forcesgravity Electrons in each shell: 2n² 2, 8, 8, 18, 18 32, 32
Building your element In pairs, you will be assigned an element card. On copy paper, draw the atomic model of your element (make 3 COPIES). DO NOT write the name of your element on the front. Under the model, copy the following in the identified color: Atomic Mass (green) Atomic radii (blue) Electronegativity (red) Ionization Energy (black)
Find a Pattern Class will be divided into 2 groups. Each group is to arrange the element cards in an arrangement that makes sense to them You MAY NOT use your periodic table. Must take into account all properties, not just atomic model
What’s the trend? Three groups will use the periodic table to organize the cards. Tape the cards to the paper in the appropriate order (account for energy levels) Group 1: Atomic Radius Group 2: Electronegativity Group 3: Ionization Energy Use a textbook (Ch. 5) to determine what your property means Find a trend with your election configuration and your property. Be able to explain to class.
Periodic Law Read Chapter 5, Section 1-2 Take notes on sheet of paper as you read.
Monday, September 25 Take out your notes (with chart) from Friday Chapter 5 Vocab Words due Tuesday (homework grade)
Copy the table in your notes DefinitionPictureTrend Atomic Radius Electronegativity Ionization Energy
Alternate Periodic Tables
Atomic Radius (Green) measure of the size of its atoms, usually the mean or typical distance from the nucleus to the boundary of the surrounding cloud of electrons nucleus electrons Radius: Trend: What is the trend of atomic radius?
Increasing
Electronegativity (red) describes the tendency of an atom to attract electrons towards itself.atomelectrons What is the trend of electronegativity?
Ionization Energy (black) The energy required to remove one electron from a neutral atom of an element What is the trend of ionization energy?
NOBILITY Stable/ unreactive. Which elements are most stable?
Periodic Law Using the new periodic table, draw arrows and label the new trends in the properties of elements on the periodic table Atomic radii (blue) Electronegativity (red) Ionization Energy (black)
The Periodic Law History of the Periodic Table
Mendeleev and Chemical Periodicity Dmitri Mendeleev noticed that when the elements were arranged in order of increasing atomic mass, certain similarities in their chemical properties appeared at regular intervals Repeating patterns = periodic Mendeleev created a table in which elements with similar properties were grouped together—a periodic table of the elements
History of the Periodic Table Mendeleev and Chemical Periodicity After Mendeleev placed all the known elements in his periodic table, several empty spaces were left In 1871 Mendeleev predicted the existence and properties of elements that would fill three of the spaces By 1886, all three of these elements had been discovered (Scandium, Gallium, Germanium)
Moseley and the Periodic Law In 1911, the English scientist Henry Moseley discovered that the elements fit into patterns better when they were arranged according to atomic number, rather than atomic weight The Periodic Law states that the physical and chemical properties of the elements are periodic functions of their atomic numbers
History of the Periodic Table Periodicity of Atomic Numbers
History of the Periodic Table The Modern Periodic Table The Periodic Table is an arrangement of the elements in order of their atomic numbers so that elements with similar properties fall in the same column, or group