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Electrons and chemical bonding

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Presentation on theme: "Electrons and chemical bonding"— Presentation transcript:

1 Electrons and chemical bonding

2 Bell work for November 25, 2018 Directions-Many Scientific words, such as bond, also have everyday meanings. Use context clues to write your own definition for each meaning of the word bond. Write your answers only, not the question 1. Zach used glue to form a bond between the broken parts of the chair. 2. A chemical bond can form between two atoms.

3 1. How do atoms join together? 2. What is a chemical bond?
Bell work for November 26, 2018 directions-Write the answers only to the questions below: 1. How do atoms join together? 2. What is a chemical bond? 3. Explain what a molecule is.

4 Where are the chemical bonds located?

5 What happens to atoms during chemical changes? Atoms are rearranged
How can you tell that atoms are not created or destroyed by the chemical change? There are the same number and type of atoms on each side

6 What do different atom models show?
Out loud Electron cloud models show how electrons are found in a region around the nucleus. (example of a hydrogen model) 1. How will an electron cloud model of Helium look? Draw it on your own sheet of loose leaf paper. Put NDC on your paper.

7 Bohr model The Bohr model shows the number of electrons in an atom. The electrons are shown as dots placed in rings around the nucleus. Bohr models do not show the true arrangement of electrons in the atom. Each ring represents an energy level, not a physical location in the atom. Showing electrons in energy levels helps predict how and why atoms form chemical bonds. (hydrogen atom) 2. How will a Bohr model of Helium look. Draw it on your own sheet of loose leaf paper. Make sure the number of protons, neutrons, and electrons are correct.

8 Space-filling model In this type of model atoms are represented as solid spheres. The spheres do not show the parts that make up the atoms. But this model clearly shows the parts that make up the atoms.

9 What are valence electrons?
Valence Electrons are electrons found in the outermost energy level. Different atoms have different numbers of valence electrons.

10 How does the periodic table show the number of valence electrons?

11 Bell work for November 27, 2018 directions-write the answers only for the questions below
1. What happens to atoms during chemical changes? 2. Describe an electron cloud model. 3. Describe a Bohr model. 4. What are valence electrons? 5. How many electrons can fit in the first energy level when drawing a Bohr model of an atom? How many electrons can fit in the second energy level. 6. How many valence electrons does a Nitrogen atom have? Phosphorus?

12 Valence electrons The Bohr model to the left show how the electrons in an oxygen atom are arranged in energy levels. An oxygen atom has eight electrons –two electrons in the first energy level and six electrons in the second energy level. In the oxygen atom, the second energy level is the outermost energy level. So, oxygen has six valence electrons. How many valence electrons does this oxygen atom have?

13 Visualize it assignment
1. Complete the “Visualize It” assignment on the left on your loose leaf paper. 2. Draw the Bohr model for Nitrogen. Be sure to include the right amount of electrons in each energy level.

14 3. Create an electron dot diagram for the following elements:
Electron dot diagrams show valence electrons (sometimes they are called Lewis dot structures) 3. Create an electron dot diagram for the following elements: Antimony, Tin, Calcium, and Potassium

15 Bell work for November 28, 2018 directions-only write the answers to the questions below
List the number of valence electrons and create an electron dot diagram for the following elements: 1. Francium 2. Radon 3.Barium 4. Astatine 5. Thallium

16 Why do atoms form bonds? An atom tends to form bonds if its outermost energy level is not full. Atoms that have fewer than eight valence electrons, except for helium, do not have a full outermost energy level. These atoms gain, lose, or share valence electrons to form bonds. Forming bonds allows atoms to fill their outermost energy level.

17 Practice identifying valence electrons
4. Draw each Bohr model and write the number of valence electrons that each atom has. 5. Circle the atoms that are likely to form chemical bonds with other atoms

18 Practice

19 Practice

20

21 Bohr model practice Now you will complete the “Bohr Model Practice” worksheet Just focus on putting the right amount of electrons in every energy level (shell) You may want to write the amount of electrons that can fit in each level on your paper if you have not printed out the notes yet: 2,8,8,18,18,32,32

22

23 Digital Lesson Review Now we will review the information using the Science Fusion digital lesson provided by the textbook


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