Key ideasThe electrons on the outermost power level of the atom are dubbed valence electrons.The valence electrons are connected in bonding one atom to another.The attraction of every atom’s nucleus because that the valence electron of the other atom traction the atom together. Together the attractions bring the atoms together, electron from every atom space attracted come the cell core of both atoms, i beg your pardon “share” the electrons. The sharing of electrons between atoms is referred to as a covalent bond, i m sorry holds the atoms with each other as a molecule.A covalent bond happens if the attractions are solid enough in both atoms and also if every atom has actually room because that an electron in that is outer energy level.Atoms will covalently bond till their outer energy level is full.Atoms covalently bonded as a molecule are much more stable than they to be as different atoms.
Students will certainly look in ~ animations and also refer to the power level models they have actually been utilizing to make drawings of the process of covalent bonding. Student will think about why atoms bond to form molecules favor H2 (hydrogen), H2O (water), O2 (oxygen), CH4 (methane), and CO2 (carbon dioxide).
Students will have the ability to explain that attraction in between the protons and electrons of 2 atoms cause them come bond. College student will be able to draw a version of the covalent bonds in between the atom in H2 (hydrogen), H2O (water), O2 (oxygen), CH4 (methane), and also CO2 (carbon dioxide).
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Download the student task sheet, and also distribute one per student as soon as specified in the activity. The activity sheet will certainly serve together the “Evaluate” ingredient of each 5-E great plan.
Be certain you and the students wear appropriately fitting goggles.
Materials because that Each Group9-volt battery2 wires through alligator clips top top both ends2 pencils sharpened at both endsWaterSaltClear plastic cupTape
About this lesson
This lesson will most likely take more than one course period.
Discuss the conditions needed because that covalent bonding and also the stable molecule the is formed.
Project the image Covalent bond in hydrogen.
Read more about bonding in the added teacher background ar at the end of this lesson.
Note: This model of covalent bonding because that the hydrogen molecule (H2) starts v 2 separation, personal, instance hydrogen atoms. In reality, hydrogen atom are never ever separate to start with. They are always bonded through something else. To simplify the process, this version does not present the hydrogen atom breaking their bonds from various other atoms. The only focuses on the procedure of creating covalent bonds between two hydrogen atoms.Two hydrogen atoms are close to each other.When two hydrogen atoms come close enough to every other, your electrons room attracted to the proton that the other atom.Because over there is both a strong enough attraction betweeen atoms and room because that electrons in the outer power level of both atoms, the atom share electrons. This creates a covalent bond.
Tell students that there room two main reasons why two hydrogen atom bond together to make one hydrogen molecule:There demands to it is in a solid enough attraction in between the electrons of every atom for the protons of the various other atom. There needs to it is in room in the outer energy level of both atoms.
Once bonded, the hydrogen molecule is much more stable than the separation, personal, instance hydrogen atoms. Explain to students that by being component of a covalent bond, the electron from each hydrogen atom gets to be close to two protons instead of only the one proton it began with. Due to the fact that the electrons space closer to more protons, the molecule of two bonded hydrogen atoms is more stable 보다 the 2 individual unbonded hydrogen atoms.
This is why it is an extremely rare to discover a hydrogen atom that is not bonded to other atoms. Hydrogen atoms bond with various other hydrogen atom to do hydrogen gas (H2). Or they deserve to bond with various other atoms prefer oxygen to do water (H2O) or carbon to do methane (CH4) or countless other atoms.
Show college student that when two hydrogen atom bond together, the outer energy level becomes full.
Have college student look at their routine table of energy levels for elements 1–20 spread in class 3.
Explain that the 2 electrons in the hydrogen molecule (H2) can be believed of together “belonging” to every atom. This means that every hydrogen atom now has two electrons in its an initial energy level. The very first energy level in the outer energy level because that hydrogen and can just accommodate or “hold” two electrons. Atom will proceed to covalently bond until their outer power levels room full. In ~ this point, extr atoms will not covalently bond to the atoms in the H2 molecule.
Have students describe covalent bonding in a hydrogen molecule on their activity sheet and also then review their answers.
Give each student an activity sheet.
Have students compose a quick caption under each photo to explain the procedure of covalent bonding and answer the an initial three questions. The rest of the activity sheet will either be completed as a class, in groups, or individually, relying on your instructions.
Ask students:What walk you create for the 2nd and third pictures of covalent bonding?Center drawing: when two hydrogen atom come near enough, their electrons are attracted come the proton the the other atom. Last drawing: This brings the atoms close enough together the they re-publishing electrons. What space two problems atoms must have in bespeak to form covalent bonds through one another? there is a strong enough attraction in between atoms and also there is room for electrons in the outer energy level of both atoms.Why is a hydrogen molecule (H2) more stable than two individual hydrogen atoms?In the hydrogen molecule, the electrons from every atom are able come be near two protons rather of just the one proton it began with. Whenever an unfavorable electrons are near extr positive protons, the setup is an ext stable.Why doesn’t a third hydrogen atom sign up with the H2 molecule to make H3? as soon as two hydrogen atoms share their electrons with each other, your outer power levels room full.
You could explain to students that when the outer power levels are full, sharing electrons with an additional atom would not take place for two key reasons:An electron native a new atom would have to join one atom in the H2 molecule on the next energy level, further from the nucleus whereby it would not feeling a solid enough attraction.An electron indigenous an atom already in the H2 molecule and close to the cell nucleus would must move further away to share with the brand-new atom.
Both of these possibilities would make the molecule less stable and also would no happen.
Have students explain covalent bonding in a water molecule ~ above their activity sheet.
Have students create a short caption next to each photo to explain the procedure of covalent bonding in the water molecule.Two hydrogen atoms and one oxygen atom are near each other.When two hydrogen atom come close sufficient to an oxygen atoms, your electrons space attracted come the proton the the various other atom.Because over there is both a strong enough attraction in between atoms and also room for electrons in the outer energy levels the the atoms, they share electrons. This creates a covalent bond.
Note: This version of covalent bonding because that a water molecule starts v 2 separation, personal, instance hydrogen atoms and also 1 oxygen atom. In reality, this atoms are never separate to begin with. Lock are constantly bonded v something else. To leveling the process, this version does not display the hydrogen and oxygen atom breaking your bonds from various other atoms. The only concentrates on the process of forming covalent bonds to do water.
Ask students:Why can’t a 3rd hydrogen atom sign up with the water molecule (H20) to do H3O? once two hydrogen atoms and also an oxygen atom share your electrons with each other, their outer energy levels space full.Explore
Have students use electrical power to break the covalent binding in water molecules.
Tell students that electric energy have the right to be used to break the covalent bond in water molecules to develop hydrogen atoms and oxygen atoms. Two hydrogen atoms climate bond to type hydrogen gas (H2) and also two oxygen atoms bond to type oxygen gas (O2).
You may pick to execute this task as a demonstration or present the video clip Electrolysis.
Question to investigate
What is produced when the covalent bond in water molecules is broken?
Materials because that each group9-volt battery2 wires through alligator clips ~ above both ends2 pencils sharpened at both endsWaterEpsom salt (magnesium sulfate)Clear plastic cupTape
ProcedurePlace a battery between 2 pencils. Be sure that the battery is more than half-way up.
With the aid of a partner, wrap tape around the pencils and also battery as shown.
Bubbles will type and rise initially from one pencil lead. Soon, bubbles will type and climb from the other. Students should have the ability to see that there is much more of one gas 보다 the other. The gas that creates the small bubbles that comes off an initial is hydrogen. The various other gas that develops the larger bubbles and also lags behind a bit is oxygen.
Note: There will certainly be bubbling once hydrogen and oxygen gas kind on the pencil leads. Be sure students do not acquire the misconception that the bubbles they see average that the water is boiling. In boiling, the bond holding the atoms together in water molecules execute not come apart. In the procedure of electrolysis, the bonds holding the atoms together do come apart.
Discuss college student observations.
Ask students:What space the bubbles made the end of in the activity?Hydrogen gas (H2) and oxygen gas (O2)Why to be there much more hydrogen gas produced than oxygen gas?Each water molecule breaks right into 2 hydrogen atoms and also 1 oxygen atom. 2 hydrogen atoms climate bond to form hydrogen gas (H2) and 2 oxygen atoms bond to kind oxygen gas (O2). Every water molecule has actually all the atoms required to do 1 molecule of hydrogen gas. Yet with only 1 oxygen atom, a water molecule only has half of what is required to do 1 molecule of oxygen gas. So, 2 water molecule will produce 2 molecules of hydrogen gas but only 1 molecule that oxygen gas.Extend
Help college student understand exactly how atoms incorporate to type the molecule of oxygen, methane, and carbon dioxide.
Remind students the in this lesson they looked at the covalent bonds in hydrogen molecules and also in water molecules. Tell them that they will look at the covalent bond in three other common substances.
Project the computer animation Oxygen’s dual bond.
Explain come students that the oxygen molecules the are present in our air are made up of 2 oxygen atoms. This computer animation will display them what the covalent bond between 2 oxygen atom is like. Narrate the animation by pointing out that each oxygen atom has actually 6 valence electrons. Once the oxygen atoms gain close together, the attractions from the cell core of both atoms entice the external electrons. In this case, 2 electrons from every atom space shared. This is called a double bond.
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