Bellwork List the topic/s you think you are an expert in and could teach someone else: 1.Density (how to calculate and solve) 2.Scientists (what they did and found) 3.Atomic structure (bohr models, P+, N o, e-) 4.Isotopes (symbol, naming, mass number, atomic number locations etc.)

Review Take out some notebook paper and a pencil If you are an expert on a topic, you will be seeking out someone who is not and help them review for 5 minutes There are 4 topics total for the quiz today

Announcements Tutoring – Fridays Quizzes – Wednesdays

Homework Collection 1.Bellwork/exit slip 2.Density homework (from half sheet) 3.Atomic numbers practice 4.Bohr model iPad practice 5.Bohr model drawings 6.Isotope worksheet

Homework Collection – Honors 1.Bellwork/exit slip 2.Density homework (from half sheet) 3.Atomic numbers practice 4.Bohr model iPad practice 5.Isotope worksheet 6.Isotope practice (half sheet) 7.Average atomic mass practice sheet 8.Average atomic mass homework

Quiz

Honors: Average Atomic Mass Continue working on average atomic mass practice You will have 30 minutes to complete the worksheet from Wednesday

Notes: The Periodic Table

Organizing the Elements Chemists used the properties of elements to sort them into groups. In 1829 J. W. Dobereiner arranged elements into triads – groups of three elements with similar properties – One element in each triad had properties intermediate of the other two elements

Mendeleev’s Periodic Table By the mid-1800s, about 70 elements were known to exist Dmitri Mendeleev – a Russian chemist and teacher arranged elements in order of increasing atomic mass Thus, the first “Periodic Table”

Mendeleev He left blanks for yet undiscovered elements When they were discovered, he had made good predictions But, there were problems  : Such as Co and Ni; Ar and K; Te and I

A better arrangement In 1913, Henry Moseley – British physicist, arranged elements according to increasing atomic number The arrangement used today

Thinking… What is one similarity and one difference between Mendeleev’s periodic table and the modern one created by Moseley?

Arrangement The periodic is arranged by groups and periods Groups run UP and DOWN Periods run LEFT and RIGHT Note this on your periodic table that I handed out

Groups are special Groups are special because all elements in one group share similar properties or characteristics such as bonding, reactivity etc. Halogens – salt formers

Exit Slip What is the difference between groups and periods on the periodic table? Why are groups special?

Bellwork Which scientist created the periodic table we use today? 2.How did he order it (ex. by increasing…)? **Pass back quizzes **Student data wall

Periodic Table Groups Alkali Metal Video 7E 7E Compound Chem – Fill out the note taker on each group using information from the website Color in periodic table as instructed ON THE NOTETAKER

When Finished… You will be creating a poster on one of the periodic table groups as a group You must include all of the information from your note taker on your periodic table group poster – Be sure to make the elements and the valence electrons MOST visible on your poster

Honors – When Finished… You will be creating a video with your group on one of the periodic table groups This video will be shared with the rest of the class and with the regular sections to help them better understand each group

Video Video must be no longer than 3 minutes Ideas: – Put on a play or skit about the group of elements you are representing – Create a commercial to sell the group of elements you are presenting Must include: – All info from your note taker

Homework Using Bohr model rules, how many valence (outer shell) electrons are in the elements on the periodic table? Valence electrons: 1 H = 2 He = 3 Li = 4 Be =