UNIT 1 Matter Day 16 Thursday, September 21, 2017 Atoms 8th Grade Science

Unit 1 Matter Day 16 Focus: Atoms 9/21/17 Pick up an “Organizing the Elements” wkst. Science starter: What do the groups/families (columns) on the periodic table tell us? Complete the element card for Oxygen. Be sure to do the Bohr and Lewis diagrams. (no properties yet)

Plan for the Day Science starter/elements of the day E.Q. Inquiry Activity – Sketch the Missing Secret Agent Notes-Metals, nonmetals, metalloids Wrap-up

Homework Complete the worksheet “Organizing the Elements” – all “reading check”, “critical thinking”, and section review. I will take this up and grade it tomorrow. Draw Bohr and Lewis diagrams for the first three element cards. Bring colored pencils tomorrow. STUDY a little each night! CFA one week from today.

How did you do on the Lewis Structures on your homework?

Essential Question page _____ – What did Dmitri Mendeleev discover as he was organizing the first periodic table?

Top Secret: Sketch the Missing Secret Agent! We are going to do an inquiry activity that will help you to begin understanding the patterns on the periodic table. Group Roles: A’s – Materials Manager B’s – Technical Manager C’s – Group Leader D’s – Safety Manager/Timekeeper There is a page of laminated instructions for each group. I will explain the instructions, but the group leader should keep them (read, explain). If you get stuck, send the technical manager for clarification. At the end, the materials manager should get all the cards back into the baggie. Bring me the cards and the laminated instruction sheets. All group members participate.

Wrap-up: How do the patterns of your secret agent table compare to the periodic table?

Let’s do an inquiry activity to help us understand how the Periodic Table of the Elements is arranged. Lay the creature cards out on the table. Look carefully at the characteristics of the creatures. Work with your group to arrange the creature cards in a 2-dimensional grid(rows and columns) with no more than 8 cards in any row. Use some characteristic of the creatures that can be used to organize them.

How many groups or families (columns) of elements are in your table? What criteria did you use to arrange your creature cards? Did you notice any repeating patterns (trends) as you organized the creature cards? Are there any exceptions to these trends? If so, which elements break the trend? Why did you arrange these elements the way you did? Are there any holes or gaps in your arrangement? Where are they? What do you think these gaps might mean?

Dmitri Mendeleev first arranged the periodic table by atomic mass Dmitri Mendeleev first arranged the periodic table by atomic mass. He had no knowledge of protons, so he couldn’t arrange the periodic table by atomic number. Still, in doing this, he was able to arrange the known elements in an organized manner, and guess what… He began to notice repeating patterns of properties (characteristics) among the elements. Later on, another scientist who had knowledge of protons, was able to arrange the p.t. by atomic number. But it changed Mendeleev’s p.table very little. Mendeleev was right on track!!!!

Not all elements had been discovered in Mendeleev’s time Not all elements had been discovered in Mendeleev’s time. So, he left a few gaps as he was arranging his periodic table. He predicted that elements would soon be discovered to fill these gaps. In 1875, a new element was discovered and named “gallium”. In 1886, another element was discovered and named “germanium”. He knew right where to fit them because of their atomic mass and their properties. Later, the last column, all gases were discovered. They fit perfectly at the end of the periodic table.

Now you know that the periodic table is arranged in a very orderly manner. Every element is in its place for a reason.

Grab your vocab. sheets.

18. Periodic Table and its History Def. - chart that organizes all known elements according to their properties Created by Dmitri Mendeleev. Arranged elements by their atomic mass. Noticed repeating patterns of physical and chemical properties. Allowed him to place elements with similar properties into the same column or group (family). Today, it is arranged by atomic number.  

Let’s begin discussing some of the major groupings on the periodic table, starting with metals.

Properties of the Three Major Categories of Elements 31. Metals 1.Shiny luster 2.Ductile 3.Good conductors of heat and electricity 4.Malleable 5.Solid @ room temperature (except Mercury-liquid) 6.Melt & boil at high temperature 7.High density Properties of the Three Major Categories of Elements Mercury

Properties of the Three Major Categories of Elements 32. Non-Metals 1.Dull (no luster) 2.Brittle; not malleable or ductile 3.Low melting & boiling points 4.Poor conductors 5.Low density 6.Opposite properties to metals 7. Most are gases Carbon

Properties of the Three Major Categories of Elements 33. Metalloids 1.Located on the stair step (zigzag) on the right side of the Table 2. Called semi-conductors (can sometimes conduct electricity) 3. Silicon is used in electronic devices 4. Properties of both metals & non-metals 5. Can be shiny or dull 6. Some are malleable and ductile, others are brittle 7. Mostly solid

Let’s shade these 3 groups n the periodic table.

Transition Elements (Metals) All metals Coinage metals; common metals Mostly shiny, ductile, malleable, good conductors, solid (except Mercury) Some are more reactive than others Ex. Iron, copper, gold, nickel, silver

Wrap-up: How did Dmitri Mendeleev arrange the Periodic Table?