Key conceptsThe electron on the outermost power level of the atom are referred to as valence electrons.The valence electrons are involved in bonding one atom come another.The attraction of every atom’s nucleus for the valence electrons of the other atom traction the atom together. As the attractions carry the atoms together, electron from every atom space attracted to the cell core of both atoms, i beg your pardon “share” the electrons. The sharing of electrons in between atoms is called a covalent bond, i m sorry holds the atoms together as a molecule.A covalent bond happens if the attractions are strong enough in both atoms and if every atom has room because that an electron in the outer power level.Atoms will certainly covalently bond till their outer energy level is full.Atoms covalently bonded as a molecule are an ext stable than they to be as different atoms.
Students will certainly look in ~ animations and refer to the power level models they have actually been utilizing to make drawings of the process of covalent bonding. Students will take into consideration why atom bond to type molecules prefer 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 also electrons of two atoms cause them to bond. Student will have the ability to draw a model 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 activity sheet, and distribute one every student as soon as specified in the activity. The activity sheet will certainly serve together the “Evaluate” ingredient of every 5-E great plan.
Be sure you and also the students wear correctly fitting goggles.
Materials because that Each Group9-volt battery2 wires v alligator clips top top both ends2 pencils sharpened at both endsWaterSaltClear plastic cupTape
About this lesson
This lesson will probably take much more than one class period.
Discuss the conditions needed because that covalent bonding and the secure molecule that is formed.
Project the picture Covalent link in hydrogen.
Read much more about bonding in the additional teacher background section at the finish 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 separate to start with. Castle are constantly bonded through something else. To simplify the process, this model does not show the hydrogen atom breaking your bonds from various other atoms. The only focuses on the process of developing covalent bonds in between two hydrogen atoms.Two hydrogen atom are near each other.When two hydrogen atom come close enough to each other, your electrons space attracted to the proton of the other atom.Because there is both a solid enough attraction betweeen atoms and room for electrons in the outer power level the both atoms, the atoms share electrons. This creates a covalent bond.
Tell students the there room two main reasons why two hydrogen atoms bond with each other to do one hydrogen molecule:There demands to it is in a solid enough attraction between the electron of each atom because that the proton of the other atom. There needs to it is in room in the outer power level that both atoms.
Once bonded, the hydrogen molecule is an ext stable 보다 the individual hydrogen atoms. Define to students the by being part of a covalent bond, the electron from every hydrogen atom gets to be close to two protons instead of just the one proton it started with. Since the electrons are closer to more protons, the molecule of two bonded hydrogen atoms is much more stable 보다 the two individual unbonded hydrogen atoms.
This is why the is an extremely rare to uncover a hydrogen atom that is no bonded to various other atoms. Hydrogen atoms bond with various other hydrogen atoms to make hydrogen gas (H2). Or they can bond with other atoms favor oxygen to do water (H2O) or carbon to do methane (CH4) or plenty of other atoms.
Show student that as soon as two hydrogen atoms bond together, the outer energy level becomes full.
Have student look in ~ their routine table of power levels for elements 1–20 dispersed in class 3.
Explain that the 2 electrons in the hydrogen molecule (H2) have the right to be assumed of together “belonging” to each atom. This way that every hydrogen atom now has actually two electrons in its first energy level. The first energy level in the outer energy level because that hydrogen and can only accommodate or “hold” 2 electrons. Atoms will proceed to covalently bond till their outer power levels are full. At this point, additional atoms will certainly not covalently bond to the atom in the H2 molecule.
Have students explain covalent bonding in a hydrogen molecule on their activity sheet and also then testimonial their answers.
Give each college student an task sheet.
Have students write a short caption under each photo to define the process of covalent bonding and answer the very first three questions. The rest of the task sheet will certainly either be completed together a class, in groups, or individually, relying on your instructions.
Ask students:What walk you write for the second and 3rd pictures the covalent bonding?Center drawing: when two hydrogen atoms come close enough, their electrons room attracted to the proton the the various other atom. Last drawing: This brings the atom close sufficient together the they share electrons. What room two problems atoms must have in stimulate to kind covalent bonds v one another? there is a solid enough attraction between atoms and also there is room because that electrons in the outer energy level the both atoms.Why is a hydrogen molecule (H2) more stable than 2 individual hydrogen atoms?In the hydrogen molecule, the electron from every atom are able come be close to two protons instead of just the one proton it started with. Whenever an adverse electrons space near additional positive protons, the arrangement is more stable.Why doesn’t a third hydrogen atom join the H2 molecule to do H3? when two hydrogen atom share your electrons v each other, their outer power levels room full.
You might explain to students that once the outer energy levels are full, share electrons with an additional atom would certainly not take place for two main reasons:An electron native a brand-new atom would need to join an atom in the H2 molecule on the next power level, additional from the nucleus whereby it would certainly not feeling a solid enough attraction.An electron indigenous an atom already in the H2 molecule and also close to the cell core would have to move more away come share through the brand-new atom.
Both of this possibilities would make the molecule much less stable and also would no happen.
Have students explain covalent bonding in a water molecule on their activity sheet.
Have students create a short caption alongside each photo to define the procedure of covalent bonding in the water molecule.Two hydrogen atoms and one oxygen atoms are close to each other.When two hydrogen atom come close sufficient to an oxygen atoms, their electrons space attracted to the proton of the various other atom.Because there is both a strong enough attraction between atoms and also room because that electrons in the outer energy levels that the atoms, castle share electrons. This creates a covalent bond.
Note: This model of covalent bonding because that a water molecule starts through 2 separation, personal, instance hydrogen atoms and 1 oxygen atom. In reality, this atoms are never separate to begin with. Castle are constantly bonded v something else. To simplify the process, this version does not show the hydrogen and oxygen atoms breaking your bonds from various other atoms. It only concentrates on the procedure of developing covalent bonds to make water.
Ask students:Why can’t a third hydrogen atom sign up with the water molecule (H20) to do H3O? when two hydrogen atoms and also an oxygen atom share their electrons v each other, their outer power levels space full.Explore
Have student use electrical energy to break the covalent bonds in water molecules.
Tell college student that electrical energy can be offered to break the covalent bond in water molecule to produce hydrogen atoms and also oxygen atoms. 2 hydrogen atoms climate bond to form hydrogen gas (H2) and two oxygen atom bond to kind oxygen gas (O2).
You may choose to perform this task as a show or present the video clip Electrolysis.
Question to investigate
What is created when the covalent link in water molecule is broken?
Materials because that each group9-volt battery2 wires through alligator clips ~ above both ends2 pencils sharpened in ~ both endsWaterEpsom salt (magnesium sulfate)Clear plastic cupTape
ProcedurePlace a battery in between 2 pencils. Be sure that the battery is an ext than half-way up.
With the help of a partner, plunder tape about the pencils and also battery together shown.
Bubbles will type and rise originally from one pencil lead. Soon, bubbles will type and climb from the other. Students should have the ability to see the there is much more of one gas 보다 the other. The gas that creates the little bubbles the comes off first is hydrogen. The various other gas that forms the bigger bubbles and also lags behind a little is oxygen.
Note: There will be bubbling when hydrogen and oxygen gas type on the pencil leads. Be sure students perform not get the misconception that the bubbles they see average that the water is boiling. In boiling, the binding holding the atoms with each other in water molecules execute not come apart. In the procedure of electrolysis, the bond holding the atoms together do come apart.
Discuss student observations.
Ask students:What room the bubbles made the end of in the activity?Hydrogen gas (H2) and oxygen gas (O2)Why was there more hydrogen gas developed than oxygen gas?Each water molecule breaks into 2 hydrogen atoms and 1 oxygen atom. 2 hydrogen atoms climate bond to kind hydrogen gas (H2) and 2 oxygen atom bond to type oxygen gas (O2). Each water molecule has actually all the atoms essential to make 1 molecule the hydrogen gas. However with only 1 oxygen atom, a water molecule just has half of what is required to make 1 molecule that oxygen gas. So, 2 water molecules will create 2 molecule of hydrogen gas but only 1 molecule that oxygen gas.Extend
Help college student understand how atoms integrate to kind the molecule of oxygen, methane, and carbon dioxide.
Remind students that in this lesson they looked at the covalent bond in hydrogen molecules and in water molecules. Tell them that they will certainly look at the covalent binding in three other common substances.
Project the animation Oxygen’s double bond.
Explain to students the the oxygen molecules that are existing in our air are made up of 2 oxygen atoms. This computer animation will show them what the covalent bond in between 2 oxygen atom is like. Narrate the animation by discussing that every oxygen atom has 6 valence electrons. Once the oxygen atoms obtain close together, the attractions indigenous the cell core of both atoms entice the outer electrons. In this case, 2 electron from each atom are shared. This is referred to as a double bond.
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