Key principles

The attractions between the protons and electrons of atoms can reason an electron to move completely from one atom to the other. When an atom loses or benefit an electron, the is called an ion. The atom the loses one electron becomes a confident ion.The atom that gains an electron becomes a an adverse ion.A positive and an adverse ion lure each various other and kind an ionic bond.

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Students will certainly look in ~ animations and make illustrations of the ionic bonding of sodium chloride (NaCl). Students will check out that both ionic and also covalent bonding begin with the attractions of protons and also electrons in between different atoms. Yet in ionic bonding, electrons space transferred from one atom to the other and not common like in covalent bonding. Students will usage Styrofoam balls to do models the the ionic bonding in sodium chloride (salt).


Students will have the ability to explain the process of the development of ions and also ionic bonds.


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


Be sure you and also the college student wear appropriately fitting goggles.

Materials because that Each Group

Black paperSaltCup through salt native evaporated saltwaterMagnifier long-term marker

Materials because that Each Student

2 small Styrofoam balls2 big Styrofoam balls2 toothpicks

Note: In an ionically external inspection substance such as NaCl, the smallest ratio of hopeful and an adverse ions bonded with each other is dubbed a “formula unit” quite than a “molecule.” Technically speaking, the term “molecule” refers to two or more atoms that space bonded with each other covalently, no ionically. For simplicity, you might want to use the hatchet “molecule” for both covalently and ionically bonded substances.


Show an animation to introduce the procedure of ionic bonding.

Project the animation Ionic shortcut in sodium chloride.

Remind students that in covalent bonding, atom share electrons. However there is another type of bonding where atoms don’t share, but instead either take it or provide up electrons. This is called ionic bonding. This computer animation shows a very simplified design of just how sodium and also chloride ions room formed.

Note: In order to simplify the version of ionic bonding, a single atom that sodium and also chlorine room shown. In reality, the chlorine atom would be bonded to an additional chlorine atom as component of the gas Cl2. The salt atom would certainly be among billions that trillions of sodium atoms bonded together as a solid. The combination of these substances is a facility reaction in between the atom of the two substances. The animation shows single separated atoms to show the idea of how ions and also ionic bonds are formed.

Explain what happens throughout the animation.

Tell students the the attraction that the protons in the sodium and chlorine for the various other atom’s electrons bring the atom closer together. Chlorine has actually a stronger attraction because that electrons than sodium (shown through the more thick arrow). At some suggest during this process, one electron indigenous the salt is transferred to the chlorine. The sodium loses one electron and also the chlorine gains an electron.

Tell students that when an atom gains or loses an electron, it i do not care an ion.

Sodium loser an electron, leaving it through 11 protons, yet only 10 electrons. Because it has actually 1 much more proton than electrons, sodium has actually a fee of +1, making the a confident ion.Chlorine gains an electron, leaving it with 17 protons and 18 electrons. Due to the fact that it has actually 1 more electron 보다 protons, chlorine has a charge of −1, making the a an unfavorable ion. Once ions form, atoms obtain or lose electrons until their outer energy level is full.For example, once sodium loser its one outer electron indigenous the third energy level, the second level i do not care the new outer power level and is full. Due to the fact that these electrons room closer come the nucleus, they are much more tightly held and also will no leave. As soon as chlorine gains an electron, its third energy level becomes full. An additional electron cannot join, because it would must come in in ~ the fourth power level. This much from the nucleus, the electron would not feel sufficient attraction indigenous the proton to be stable. Then the positive sodium ion and negative chloride ion lure each various other and form an ionic bond. The ion are more stable as soon as they space bonded than they were together individual atoms.

Have students explain the procedure of ionic bonding in salt chloride on their task sheet.

Give each student an task sheet.

Have students create a short caption under each snapshot to describe the process of covalent bonding and answer the an initial three questions. The rest of the activity sheet will certainly either it is in completed together a class, in groups, or individually relying on your instructions.

Project the photo Ionic shortcut in salt chloride.

Review through students the process of ionic bonding covered in the animation.

Help students compose a quick caption beside each snapshot to explain the process of ionic bonding in sodium and also chloride ions.

Sodium and also chlorine atoms are near each other.The proton of the two atoms attract the electron of the other atom. The thicker arrowhead shows the chlorine has a stronger attraction because that electrons than sodium has.During the interactions in between the atoms, the electron in sodium"s outer energy level is moved to the outer power level the the chlorine atom.Since sodium shed an electron, it has actually 11 protons, but only 10 electrons. This makes sodium a optimistic ion through a fee of +1. Because chlorine obtained an electron it has actually 17 protons and also 18 electrons. This renders chloride a an adverse ion v a charge of −1.The positive sodium ion and an unfavorable chloride ion attract one another. They make an ionic bond and type the ionic link NaCl.Explore

Have students watch actual sodium chloride crystals and relate their form to the molecule model.

This two-part task will assist students watch the relationship in between the arrangement of ions in a model of a sodium chloride crystal and the cubic form of actual sodium chloride crystals.

Teacher preparation

The day prior to the lesson, dissolve about 10 grams that salt in 50 mL the water. Usage Petri dishes or use scissors to cut down 5 or 6 clear plastic cup to do shallow plastic dishes. Pour sufficient saltwater to just cover the bottom of each dish (1 for each group). Leaving the key overnight to evaporate for this reason that brand-new salt crystals will certainly be produced.

Materials because that each group

Black paperSaltCup through salt native evaporated saltwaterMagnifier irreversible marker

Materials for each student

2 tiny Styrofoam balls2 huge Styrofoam balls2 toothpicks

Procedure, component 1

Observe sodium chloride crystals.Place a few grains the salt on a piece of black color paper. Use your magnifier come look very closely at the salt.

Have students develop a 3-dimensional design of salt chloride.

Each student will certainly make 1 unit of sodium chloride. Student in each group will placed their salt chloride units together. You can help the groups incorporate their structures into a class model of a salt chloride crystal.

Procedure, component 2

Make NaCl units.Use the marker to placed a “−” top top the huge balls which stand for chloride ions.Use the marker to put a “+” top top the little balls, which stand for sodium ions.Break 2 toothpicks in half. Use among the half-toothpicks to attach the centers that the small and large ions with each other to do a unit of sodium chloride (NaCl). Perform the exact same thing v the other tiny and large ball.

Use an additional half-toothpick to affix the 2 NaCl devices in a straight line as shown.

Put NaCl ions together to do one great of ions.Contribute her line of ions to her group and also arrange lock to do a 4×4 square that ions.

Use half-toothpicks to affix the end of each line to organize the ions together. You only need to place toothpicks in the balls in ~ the finish of every line.

Build a class sodium chloride crystal.

Give her group’s layer of ions to your teacher. Your teacher will stack this to develop a version of a salt chloride crystal.


Point the end that almost everywhere you look on the crystal, a salt ion and a chloride ion are always surrounded by the oppositely charged ion. This opposite charges organize the ions together in a crystal.


Ask students

Based on the way sodium and also chloride ions bond together, why are salt crystals shaped choose cubes?The size and arrangement the the ions forms a cube ~ above the molecule level. Since the pattern repeats over and over again in the same way, the shape stays the same even when the decision becomes the normal size that we can see.Extend

Show students how calcium and chlorine atoms bond to type the ionic link calcium chloride.

Tell students that there is an additional common substance called calcium chloride (CaCl2). The is the salt the is supplied on icy sidewalks and also roads. Describe that when calcium and chlorine react they create ions, prefer sodium and also chlorine, but the calcium ion is various from the sodium ion.

Ask students:

What ions perform you think CaCl2 is make of? One calcium ion and also two chloride ions.

Project the animation Calcium chloride Ionic Bond.

Point the end that the calcium loses two electrons, becoming a +2 ion. Each of the two chlorine atom gains one of these electrons, do them every a −1 ion. Aid students realize that 1 calcium ion bonds with 2 chloride ion to kind calcium chloride (CaCl2), i m sorry is neutral.

Some atoms gain or lose much more than 1 electron. Calcium loser 2 electrons as soon as it becomes an ion. When ions come with each other to type an ionic bond, they always join in numbers that precisely cancel the end the hopeful and an unfavorable charge.

Project the photo Calcium chloride Ionic Bond.

Review through students the process of ionic bonding spanned in the animation.

Have students compose a brief caption beneath each photo to explain the procedure of ionic bonding in sodium and chloride ions.

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One calcium and also two chlorine are close to each other.The protons of the calcium atom tempt the electrons from the chlorine atom. The proton of the two chlorine atoms attract the electron from the calcium atom more strongly as presented by the more thickness arrows.During the interactions between the atoms, the 2 electrons in calcium"s outer energy level are transferred come the outer power level of every of the chlorine atoms.Since calcium shed two electrons, it has actually 20 protons, yet only 18 electrons. This provides calcium a positive ion v a charge of 2+. Due to the fact that each chlorine atom acquired an electron, lock each have actually 17 protons and also 18 electrons. This renders each chloride a negative ion v a charge of −1.Oppositely charged ions entice each other, developing an ionic bond. The bonded ion are more stable 보다 the individual atoms were.