Middle+School+Chemistry+Chapter+4

=You Tube Atoms Playlist= = = =Chapter 4, Lesson 1: Protons, Neutrons, and Electrons= media type="custom" key="24128196" Brain Pop: Ions

Key Concepts

 * Atoms are made of extremely tiny particles called protons, neutrons, and electrons
 * Protons and neutrons are in the center of the atom, making up the nucleus
 * Electrons surround the nucleus
 * Protons have a positive charge
 * Electrons have a negative charge
 * The charge on the proton and electron are exactly the same size but opposite
 * Neutrons have no charge
 * Since opposite charges attract, protons and electrons attract each other

Objective
Students will be able to explain, in terms of electrons and protons, why a charged object is attracted or repelled by another charged object. They will also be able to explain why a charged object can even be attracted to an uncharged object. Students will also be able to explain that the attraction between positive protons and negative electrons holds an atom together.

Materials Needed

 * Plastic grocery bag
 * Scissors
 * Inflated balloon
 * Small pieces of paper, confetti-size
 * Sink

All About Atoms


 * 1) What are the three different tiny particles that make up an atom? Which of these is in the center of the atom? What zoom around the nucleus of an atom? Which one has a positive charge, a negative charge, and no charge? Answer these questions, & draw a diagram on the atoms worksheet.
 * 2) media type="file" key="protons_and_electrons.swf" width="360" height="270" Two protons repel each other and two electrons repel each other. **But a proton and an electron attract each other.** ("Like" charges repel and opposite charges attract)
 * 3) media type="file" key="hydrogen_atom.swf" width="360" height="270"In a hydrogen atom, the negatively charged electron is attracted to the positively charged proton. This attraction is what holds the atoms together. **Hydrogen is the simplest atom. It has only 1 proton, 1 electron, and 0 neutrons.**
 * 4) Click on the button "show cloud" in the above animation. This shows the electron in the space surrounding the nucleus that is called an electron cloud or energy level. it is not possible to know the location of an electron but only the region where it is most likely to be. The electron cloud or energy level shows the region surrounding the nucleus where the electron is most likely to be.
 * 5) Answer the questions on your activity sheet about the information above.
 * 6) Watch "Bill Nye the Science Guy - Atoms" on your iPad
 * 7) Complete the activity and record your observations
 * 8) Complete the Take it Further activity and record your observations
 * 9) Do you think electrons can attract a stream of water? Write your hypothesis on the back of your activity sheet. Then do the following experiment:
 * Rub a balloon on your shirt to give it a static charge
 * Turn on the faucet so that there is a very thin stream of water
 * Slowly bring the charged part of the balloon close to the stream of water
 * Record your observations - Use what you know about electrons, protons, and charges to explain what happened

=Chapter 4, Lesson 2: The Periodic Table= media type="custom" key="24789268" media type="custom" key="24808168" Making the Periodic Table Fun The Elements: A Visual Exploration (App on your iPad) Periodic Table Live! Chemical Elements and Their Symbols

Key Concepts

 * The periodic table is chart containing information about the atoms that make up all matter
 * An element is a substance made up of only one type of atom
 * The atomic number of an atom is equal to the number of protons in its nucleus
 * The number of electrons surrounding the nucleus of an atom is equal to the number of protons in its nucleus
 * Different atoms of the same element can have a different number of neutrons
 * Atoms of the same element with different numbers of neutrons are called "isotopes" of that element
 * The atomic mass of an element is the average mass of the different isotopes of the element
 * The atoms in the periodic table are arranged to show characteristics and relationships between atoms and groups of atoms

Key Words

 * Atom:** the smallest particle or "building block" of a substance
 * Element:** substance made up of all the SAME type of atom

Objective
Students will identify different atoms by the number of protons in the nucleus and realize that the number of electrons equal the number of protons in a neutral atom. They will also be able to explain the meaning of atomic number and atomic mass media type="custom" key="24797056"
 * 1) Look at the periodic table printout. Each box contains information about a different atom. The periodic table shows all the atoms that everything in the known universe is made from. It's kind of like the alphabet in which only 26 letters, in different combinations, make up many thousands of works. The 100 or so atoms of the periodic table, in different combinations, make up millions of different substances.
 * 2) Listen to the following song: The Elements
 * 3) [[image:http://www.middleschoolchemistry.com/img/content/multimedia/chapter_4/lesson_2/periodic_table_legend.jpg]]
 * 4) Review the definitions of Proton, Electron, & Neutron.
 * 5) Choose two elements to do further research. Do a poster, pamphlet, PowerPoint presentation or some other form of presentation about your elements. Should include the atom name, atomic number, derivation of name, when and where it was discovered, natural sources of the element, major uses, and any other information you find important.

=Chapter 4, Lesson 3: The Periodic Table and Energy-Level Models=

Brain Pop: Periodic Table

Key Concepts

 * The electrons surrounding an atom are located in regions around the nucleus called "energy levels"
 * An energy level represents the 3-dimensional space surrounding the nucleus where electrons are most likely to be
 * The first energy level is closest to the nucleus. The second energy level is a little farther away than the first. The third is a little farther away than the second, and so on.
 * each energy level can accommodate or "hold" a different number of electrons before additional electrons begin to go into the next level
 * When the first energy level has 2 electrons, the next electrons go into the second energy level until the second level has 8 electrons
 * When the second energy level has 8 electrons, the next electrons go into the third energy level until the third level has 8 electrons
 * When the third energy level has 8 electrons, the next 2 electrons go into the fourth energy level
 * The electrons in the energy level farthest from the nucleus are called valence electrons
 * Atoms in the same column (group) in the periodic table have the same number of valence electrons

Objective
Students will be able to interpret the information given in the periodic table to describe the arrangement of electrons on the energy levels around an atom


 * 1) Look at your activity sheet at the cross-section of the atom. Electrons surround the nucleus of an atom in three dimensions, making atoms spherical. Think of electrons as being in the different energy levels like concentric spheres around the nucleus. Since it is difficult to show the spheres, the energy levels are typically shown in 2 dimensions.
 * 2) [[image:http://www.middleschoolchemistry.com/img/content/multimedia/chapter_4/lesson_3/oxygen_atom.jpg]] This energy level model represents an atom. The nucleus is represented by a dot in the center, which contains both protons and neutrons. The smaller dots surrounding the nucleus represent electrons in the energy levels.
 * 3) Look at the periodic table of the elements 1-20 from last lesson. C an you identify which atom this model represents?
 * 4) Review the Energy Levels for Elements 1-20 sheet. The rows across on the periodic table are called //periods.// Fill in the correct number of electrons in the energy levels on the ones not already completed.

Period 1

 * //Hydrogen -// hydrogen has 1 proton and 1 electron. The 1 electron is on the first energy level
 * //Helium -// helium has 2 protons and 2 electrons. The 2 electrons are on the first energy level

Period 2

 * //Lithium -// lithium has 3 protons and 3 electrons. There are 2 electrons on the first energy level and 1 electron on the second. The first energy level can only have 2 electrons so the next electron in lithium is on the next (second) level.
 * //Neon -// neon has 10 protons and 10 electrons. There are 2 electrons on the first energy level and 8 electrons on the second level

Period 3
>
 * //Sodium -// sodium has 11 protons and 11 electrons. There are 2 electrons on the first energy level, 8 electrons on the second level, and 1 electron on the third energy level. The second energy level can only have 8 electrons so the next electron in sodium has to be on the next (third) level
 * //Argon -// argon has 18 protons and 18 electrons. There are 2 electrons on the first energy level, 8 electrons on the second level, and 8 electrons on the third energy level.

Period 4

 * //Potassium -// potassium has 19 protons and 19 electrons. There are 2 electrons on the first energy level, 8 electrons on the second level, 8 electrons on the third energy level, and 1 on the fourth energy level. After the third energy level has 8 electrons, the next electron goes into the fourth level.

The vertical columns in the periodic table are called //groups or families.// Compare the number of electrons in the outermost energy level for the atoms in a group. What do you notice?

In the periodic table atoms in the same column, called a group, share certain characteristics and can react in a similar way. Go online and watch the videos: Sodium in water; Potassium in water; Calcium in water; Sodium in acid; Potassium in acid; Calcium in acid

Chapter 4, Lesson 4: Energy Levels, Electrons, and Covalent Bonding
media type="custom" key="24821298"media type="custom" key="24821352"

Key Concepts

 * The electrons on the outermost energy level of the atom are called valence electrons
 * The valence electrons are involved in bonding one atom to another
 * The attraction of each atom's nucleus for the valence electrons of the other atoms pulls the atoms together
 * As the attractions bring the atoms together, electrons from each atom are attracted to the nucleus of both atoms, which "share" the electrons
 * The sharing of electrons between atoms is called a covalent bond, which holds the atoms together as a molecule
 * A covalent bond happens if the attractions are strong enough in both atoms and if each atom has room for an electron in its outer energy level
 * Atoms will covalently bond until their outer energy level is full
 * Atoms covalently bonded as a molecule are more stable than they were as separate atoms

Objective
Students will be able to explain that attraction between the protons and electrons of two atoms cause them to bond. Students will be able to draw a model of the covalent bonds between the atoms in H2 (hydrogen), H20 (water), O2 (oxygen), CH4 (methane), and CO2 (carbon dioxide).

Materials Needed

 * 9-volt battery
 * 2 wires with alligator clips on both ends
 * 2 pencils sharpened at both ends
 * water
 * salt
 * clear plastic cup
 * tape

media type="file" key="covalent_bond_hydrogen.swf" width="360" height="270"Remember that the electron and its own proton are attracted to each other. If the atoms get close enough to each other, the electron from each hydrogen atom feels the attraction from the proton o the other hydrogen atom. The attractions are not strong enough to pull the electron completely away from its own proton, but the attractions are strong enough to pull the two atoms close enough together so that the electrons feel the attraction from both protons and are shared by both atoms. At the end of this animation, the individual hydrogen atoms have now bonded to become the molecule H2. This type of bond is called a //covalent// bond, electrons from each atom are attracted or "shared" by both atoms.


 * 1) Look at #1 on your activity sheet. Two hydrogen atoms are near each other. When they com close enough, their electrons are attracted to the proton of the other atom. Because there is both a strong enough attraction between atoms and room for electrons in the outer energy level of both atoms, the atoms share electrons. This forms a covalent bond. There are two main reasons why two hydrogen atoms bond together to make one hydrogen molecule:
 * There needs to be a strong enough attraction between the electrons of each atom for the protons of the other atom
 * There needs to be room in the outer energy level of both atoms

Once bonded, the hydrogen molecule is more stable than the individual hydrogen atoms. By being part of a covalent bond, the electron from each hydrogen atom gets to be near two protons instead of only the one proton it started with. Since the electrons are closer to more protons, the molecule o two bonded hydrogen atoms is more stable than the two individual unbonded hydrogen atoms. That is why it is very rare to find a hydrogen atom that is not bonded to other atoms. Hydrogen atoms bond with other hydrogen atoms to make hydrogen gas (H2). Or they can bond with other atoms like oxygen to make water (H20) or carbon to make methane (CH4) or many other atoms.

2. Review your Periodic table of energy levels for elements 1-20 (from lesson 3). The two electrons in the hydrogen molecule (H2) can be thought of as "belonging" to each atom. This means that each hydrogen atom now has two electrons in its first energy level. The first energy level in the outer energy level for hydrogen and can only accommodate or "hold" two electrons. atoms will continue to covalently bond until their outer energy levels are full. t this point, additional atoms will not covalently bond to the atoms in the H2 molecule.

3. Describe covalent bonding in a hydrogen molecule on your activity sheet.

media type="file" key="covalent_bond_water.swf" width="360" height="270" 4. Watch the video & complete question 5 on your activity sheet. 5. Electrical energy can be used to break the covalent bonds in water molecules to produce hydrogen atoms and oxygen atoms. Two hydrogen atoms then bond to form hydrogen has (H2) and two oxygen atoms bond to form oxygen gas (02). Complete the activity to demonstrate.

media type="file" key="electrolysis.wmv" width="300" height="300" 6. Complete the Take It Further portion of your activity sheet.

Key Concepts

 * The attractions between the protons and electrons of atoms can cause an electron to move completely from one atom to the other
 * When an atom loses or gains an electron, it is called an ion
 * The atom that loses an electron becomes a positive ion
 * The atom that gains an electron becomes a negative ion
 * A positive and negative ion attract each other and form an ionic bond

Objective
Students will be able to explain the process of the formation of ions and ionic bonds

Materials Needed

 * 2 small Styrofoam balls
 * 2 large Styrofoam balls
 * 2 toothpicks
 * Black paper
 * salt
 * cup with salt from evaporated saltwater
 * magnifier
 * permanent marker


 * 1) Watch the video at this link: Sodium and chlorine react. Chlorine is a greenish poisonous gas and sodium is a shiny, soft, and very reactive metal. But when they reac, they form sodium chloride (table salt). In this video, the drop of water helps expose the atoms at the surface of the sodium so that they can react with the chlorine. The formation of the salt crystals releases a lot of energy. (The salt we eat is NOT made this way - salt on Earth was produced billions of years ago but probably not from pure chlorine gas and sodium metal)
 * 2) media type="file" key="ionic_bond_sodium_chloride.swf"Remember that in //covalent// bonding, atoms share electrons. But there is another type of bonding where atoms don't share, but instead either take or give up electrons. This is called //**ionic bonding.**//  Use your molecule kit and make a sodium/chlorine atom.
 * 3) Define //ion// in your science notebook
 * 4) Define the process of ionic bonding in sodium chloride on your activity sheet.
 * 5) Write a caption beside each picture on your activity sheet to describe the process of ionic bonding
 * 6) media type="file" key="sodium_chloride_crystal.wmv"**Remember that the scale of any model of atoms, ions, or molecules is enormous compared the the actual size. In a single grain of salt there are BILLIONS of TRILLIONS of sodium and chloride ions!!** Answer the following questions in your science notebook:
 * What ion is the larger ball with the negative charge?
 * What made it negative?
 * What is the ion with the positive charge?
 * What made it positive?

7. Complete the procedure outlined on your activity sheet. Record your observations. 8.

There is another common substance called calcium chloride (CaCl2). It is the salt that is used on icy sidewalks and roads. When calcium and chlorine react they produce ions, like sodium and chlorine, but the calcium ion is different from the sodium ion. media type="file" key="calcium_chloride_ion.swf" 9. Complete the Take it Further section of your activity sheet.

Key Concepts

 * There are shorthand ways to represent how atoms form covalent or ionic bonds
 * Lewis dot diagrams use dots arranged around the atomic symbol to represent the electrons in the outermost energy level of an atom
 * Single bonds are represented by a pair of dots or one line between atoms
 * Double bonds are represented by two pairs of dots or two lines between atoms
 * Triple bonds are represented by three pairs of dots or three lines between atoms

Objective
Students will be introduced to the basics of Lewis dot diagrams as they compare the energy level models used in chapter 4 to dot diagrams. They will review the Lewis dot diagrams for a few common covalent and ionic compounds.

media type="custom" key="24920556"

One popular method of representing atoms is through Lewis dot diagrams. In a dot diagram, only the symbol for the element and the electrons in its outermost energy level (valence electrons) are shown.


 * 1) Compare the periodic table of energy levels to the Lewis dot diagrams. Look at the dots around each symbol and the energy levels in your chart. What relationship do you notice? Write your observation on your activity sheet.
 * 2) Review the models of covalent bonding in hydrogen. In a dot diagram, the electrons that are shared in the bond are placed between the symbol for each atom. The electrons between the two atoms are shared and are counted as belonging to each atom. In the energy level model for the hydrogen molecule, two electrons are shared. The Lewis dot diagram for the hydrogen molecule also shows that two electrons are shard. There is an even more shorthand approach that shows the bond as a line. The line represents one pair of electrons.
 * 3) Review the model of Covalent bonding in water. Notice that the number of dots around the oxygen atom in the Lewis diagram is the same as the number of electrons in the outer energy level of the energy level model.
 * 4) Review the model of Covalent bonding in oxygen. Two pair of electrons are shared. The remaining electrons are shown paired up around each oxygen atom. In the Lewis dot diagram, there are two lines because there are two pairs of electron that are shared.
 * 5) Review the model of Covalent bonding in carbon dioxide. In the energy level model, two pairs of electrons are shared with each oxygen atom. The Lewis dot diagram also shows that two pairs of electrons are shared. The remaining electrons are shown paired up around each oxygen atom. In the Lewis dot diagram, there are two lines between each atom to show that two pairs of electrons are shared.
 * 6) Lewis dot diagrams can also represent ionic bonding. Review the Ionic bonding of sodium chloride and calcium chloride. Answer the following questions in your science notebook:
 * In the second dot diagram, why are there no electrons surrounding sodium?
 * In the final dot diagram of NaCl, the dots between the sodium and chlorine are between the atoms. Are these atoms sharing the electrons?
 * What do you think the 2+ near the calcium means?
 * In the final dot diagram of CaCl2, the dots between the calcium and chlorin are between the atoms. Are these atoms sharing the electrons?

Chapter 4: Review and Reflect

 * 1) Complete the student reading for this unit
 * 2) Chemical Bonding Flash Cards Do a quick review
 * 3) Take the quiz