Key principles

The electron on the outermost power level the the atom are called valence electrons.The valence electrons are involved in bonding one atom to another.The attraction of every atom’s nucleus because that the valence electrons of the other atom traction the atom together. Together the attractions bring the atom together, electron from every atom are attracted come the cell core of both atoms, i m sorry “share” the electrons. The share of electrons between atoms is dubbed a covalent bond, which holds the atoms together as a molecule.A covalent bond wake up if the attractions are solid enough in both atoms and also if every atom has room for an electron in that 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 were as different atoms.

Summary

Students will certainly look in ~ animations and refer to the energy level models they have actually been utilizing to make illustrations of the procedure of covalent bonding. Students will take into consideration why atoms bond to kind molecules favor H2 (hydrogen), H2O (water), O2 (oxygen), CH4 (methane), and CO2 (carbon dioxide).

Objective

Students will be able to explain that attraction in between the protons and electrons of 2 atoms reason them come bond. College student will be able 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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Evaluation

Download the student task sheet, and also distribute one per student as soon as specified in the activity. The activity sheet will serve together the “Evaluate” component of every 5-E great plan.

Safety

Be certain you and the student wear properly fitting goggles.

Materials for Each Group

9-volt battery2 wires with alligator clips top top both ends2 pencils sharpened at both endsWaterSaltClear plastic cupTape

About this lesson

This class will most likely take much more than one class period.


Explain

Discuss the conditions needed because that covalent bonding and also the stable molecule that is formed.

Project the image Covalent shortcut in hydrogen.

Read more about bonding in the additional teacher background ar at the end of this lesson.

Note: This version of covalent bonding for the hydrogen molecule (H2) starts v 2 individual hydrogen atoms. In reality, hydrogen atoms are never separate to begin with. Lock are constantly bonded with something else. To leveling the process, this version does not display the hydrogen atom breaking your bonds from other atoms. That only focuses on the process of developing covalent bonds in between two hydrogen atoms.

Two hydrogen atom are close to each other.When 2 hydrogen atoms come close sufficient to every other, their electrons room attracted come the proton the the various other atom.Because over there is both a strong enough attraction betweeen atoms and room for electrons in the outer power level that both atoms, the atom share electrons. This forms a covalent bond.

Tell students the there are two key reasons why two hydrogen atoms bond with each other to do one hydrogen molecule:

There requirements to be a solid enough attraction in between the electrons of every atom for the protons of the other atom. There demands to it is in room in the outer power level that both atoms.

Once bonded, the hydrogen molecule is an ext stable than the individual hydrogen atoms. Describe to students that by being part of a covalent bond, the electron from each hydrogen atom gets to be near two protons rather of only the one proton it began with. Because the electrons room closer to more protons, the molecule of two bonded hydrogen atom is more stable than the two individual unbonded hydrogen atoms.

This is why it is very rare to find a hydrogen atom the is no bonded to various other atoms. Hydrogen atoms bond with other hydrogen atoms to make hydrogen gas (H2). Or they deserve to bond with other atoms choose oxygen to do water (H2O) or carbon to do methane (CH4) or countless other atoms.

Show college student that as soon as two hydrogen atom bond together, the outer energy level becomes full.

Have students look in ~ their periodic table of energy levels for elements 1–20 distributed in class 3.

Explain that the 2 electrons in the hydrogen molecule (H2) have the right to be thought of as “belonging” to every atom. This method that every hydrogen atom now has actually two electron in its very first energy level. The first energy level in the outer energy level because that hydrogen and also can only accommodate or “hold” two electrons. Atom will proceed to covalently bond till their outer power levels are full. In ~ this point, extr atoms will not covalently bond come the atoms in the H2 molecule.

Have students describe covalent bonding in a hydrogen molecule top top their activity sheet and also then review their answers.

Give each student an task sheet.

Have students compose a short caption under each snapshot to explain the process of covalent bonding and also answer the first three questions. The rest of the activity sheet will certainly either be completed as a class, in groups, or individually, depending upon your instructions.

Ask students:

What go you write for the second and third pictures of covalent bonding?Center drawing: when two hydrogen atom come nearby enough, your electrons room attracted to the proton the the other atom. Last drawing: This bring the atom close enough together the they re-publishing electrons. What space two conditions atoms must have actually in bespeak to type covalent bonds with one another? there is a solid enough attraction in between atoms and there is room because that electrons in the outer energy level that both atoms.Why is a hydrogen molecule (H2) more stable than 2 individual hydrogen atoms?In the hydrogen molecule, the electron from every atom room able come be close to two protons rather of just the one proton it began with. Whenever negative electrons are near added positive protons, the arrangement is an ext stable.Why doesn’t a third hydrogen atom join the H2 molecule to do H3? as soon as two hydrogen atom share your electrons v each other, their outer power levels are full.

You could explain come students that as soon as the outer power levels are full, sharing electrons with one more atom would certainly not happen for two main reasons:

An electron native a brand-new atom would need to join one atom in the H2 molecule ~ above the next energy level, more from the nucleus wherein it would not feeling a solid enough attraction.An electron from an atom currently in the H2 molecule and also close to the cell nucleus would should move additional away come share with the brand-new atom.

Both of these possibilities would certainly make the molecule less stable and also would no happen.

Have students describe covalent bonding in a water molecule ~ above their task sheet.

Have students create a brief caption alongside each picture to explain the procedure of covalent bonding in the water molecule.

Two hydrogen atoms and also one oxygen atoms are near each other.When 2 hydrogen atom come close enough to one oxygen atoms, their electrons space attracted come the proton the the various other atom.Because there is both a strong enough attraction in between atoms and room because that electrons in the outer power levels of the atoms, castle share electrons. This forms a covalent bond.

Note: This design of covalent bonding because that a water molecule starts v 2 individual hydrogen atoms and also 1 oxygen atom. In reality, this atoms are never ever separate to begin with. They are always bonded v something else. To simplify the process, this design does not present the hydrogen and also oxygen atom breaking your bonds from various other atoms. That only focuses on the procedure of developing covalent bond to make water.

Ask students:

Why can’t a third hydrogen atom sign up with the water molecule (H20) to make H3O? as soon as two hydrogen atoms and an oxygen atom share their electrons v each other, their outer power levels space full.Explore

Have student use electricity to break the covalent binding in water molecules.

Tell college student that electrical energy have the right to be offered to rest the covalent bond in water molecules to create hydrogen atoms and oxygen atoms. Two hydrogen atoms climate bond to form hydrogen gas (H2) and two oxygen atoms bond to form oxygen gas (O2).

You may select to execute this task as a demonstration or show the video Electrolysis.

Question to investigate

What is created when the covalent bond in water molecule is broken?

Materials for each group

9-volt battery2 wires v alligator clips on both ends2 pencils sharpened at both endsWaterEpsom salt (magnesium sulfate)Clear plastic cupTape

Procedure

Place a battery in between 2 pencils. Be certain that the battery is an ext than half-way up.

With the assist of a partner, wrap tape roughly the pencils and battery together shown.

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Add water to a clean plastic cup till it is about ½-full. Add about ½ teaspoon of Epsom salt come the water and stir till the salt dissolves. Affix one alligator clip to one terminal of the battery.Using the other wire, affix one alligator clip to the other terminal of the battery.Connect one end of the pencil lead to the alligator clip in ~ the finish of among the wires.Using the various other wire, affix one finish of the various other pencil cause the alligator clip in ~ the finish of the wire.Place the end of the pencil right into the water together shown.

Expected results

Bubbles will kind and rise originally from one pencil lead. Soon, balloon will form and rise from the other. College student should be able to see the there is more of one gas 보다 the other. The gas that develops the small bubbles the comes off an initial is hydrogen. The various other gas that develops the bigger bubbles and lags behind a bit is oxygen.

Note: There will be bubbling as soon as hydrogen and also oxygen gas kind on the pencil leads. Be certain students perform not obtain the misconception the the balloon they see median that the water is boiling. In boiling, the bonds holding the atoms together in water molecules carry out not come apart. In the process of electrolysis, the binding holding the atom together carry out come apart.

Discuss student observations.

Ask students:

What are the bubbles made the end of in the activity?Hydrogen gas (H2) and oxygen gas (O2)Why was there an ext hydrogen gas developed than oxygen gas?Each water molecule breaks 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). Each water molecule has actually all the atoms needed to make 1 molecule that hydrogen gas. But with only 1 oxygen atom, a water molecule only has fifty percent of what is essential to make 1 molecule that oxygen gas. So, 2 water molecules will develop 2 molecule of hydrogen gas however only 1 molecule the oxygen gas.Extend

Help college student understand exactly how atoms combine to type the molecules of oxygen, methane, and carbon dioxide.

Remind students the in this lesson they looked in ~ the covalent bonds in hydrogen molecules and also in water molecules. Call them that they will certainly look in ~ the covalent bond in 3 other usual substances.

Project the 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 animation will show them what the covalent bond in between 2 oxygen atoms is like. Narrate the animation by discussing that each oxygen atom has actually 6 valence electrons. When the oxygen atoms obtain close together, the attractions from the cell core of both atoms tempt the external electrons. In this case, 2 electrons from each atom room shared. This is referred to as a dual bond.

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Each oxygen atom has 6 valence electron in that outer energy levelWhen two oxygen atoms gain close to every other, the attractions from the cell core of both atoms entice the outer electrons.