Key principles

The attractions in between the protons and also electrons of atoms can reason an electron come move totally from one atom to the other. As soon as an atom loses or profit an electron, the is called an ion. The atom the loses one electron becomes a hopeful ion.The atom that gains one electron becomes a an unfavorable ion.A confident and an adverse ion tempt each various other and form an ionic bond.

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Students will look at animations and make illustrations of the ionic bonding of sodium chloride (NaCl). Student will see that both ionic and also covalent bonding begin with the attractions the protons and electrons in between different atoms. But in ionic bonding, electrons room transferred indigenous one atom come the other and also not mutual like in covalent bonding. Student will use Styrofoam balls to do models that the ionic bonding in sodium chloride (salt).


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


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


Be certain you and the students wear effectively fitting goggles.

Materials because that Each Group

Black paperSaltCup through salt from evaporated saltwaterMagnifier irreversible marker

Materials because that Each Student

2 little Styrofoam balls2 big Styrofoam balls2 toothpicks

Note: In one ionically external inspection substance such as NaCl, the smallest ratio of confident and negative ions bonded with each other is called a “formula unit” quite than a “molecule.” Technically speaking, the hatchet “molecule” describes two or much more atoms that space bonded together covalently, no ionically. For simplicity, you might want to use the hatchet “molecule” for both covalently and also ionically external inspection substances.


Show an computer animation to introduce the procedure of ionic bonding.

Project the animation Ionic shortcut in salt chloride.

Remind students the in covalent bonding, atoms share electrons. Yet there is another form of bonding where atoms don’t share, however instead either take it or provide up electrons. This is called ionic bonding. This animation shows a really simplified version of exactly how sodium and chloride ions are formed.

Note: In bespeak to simplify the model of ionic bonding, a single atom the sodium and also chlorine space shown. In reality, the chlorine atom would be external inspection to an additional chlorine atom as component of the gas Cl2. The sodium atom would certainly be among billions the trillions of sodium atoms bonded together as a solid. The mix of this substances is a facility reaction between the atom of the 2 substances. The computer animation shows single separated atoms to show the idea of how ions and also ionic bonds room formed.

Explain what happens during the animation.

Tell students the the attraction that the protons in the sodium and chlorine because that the other atom’s electrons brings the atom closer together. Chlorine has a stronger attraction because that electrons 보다 sodium (shown by the thicker arrow). In ~ some suggest during this process, one electron from the salt is transferred to the chlorine. The salt loses one electron and the chlorine profit an electron.

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

Sodium loser an electron, leave it v 11 protons, yet only 10 electrons. Since it has actually 1 much more proton 보다 electrons, sodium has a fee of +1, making the a optimistic ion.Chlorine gains an electron, leaving it with 17 protons and also 18 electrons. Because it has actually 1 more electron 보다 protons, chlorine has a charge of −1, making that a negative ion. As soon as ions form, atoms gain or shed electrons until their outer energy level is full.For example, as soon as sodium loses its one external electron from the third energy level, the 2nd level i do not care the brand-new outer power level and also is full. Since these electrons space closer come the nucleus, castle are much more tightly held and also will not leave. When chlorine profit an electron, its 3rd energy level becomes full. Secondary electron cannot join, since it would should come in at the fourth power level. This much from the nucleus, the electron would certainly not feel enough attraction indigenous the protons to it is in stable. Climate the hopeful sodium ion and negative chloride ion entice each other and kind an ionic bond. The ion are more stable when they space bonded 보다 they were together individual atoms.

Have students define the procedure of ionic bonding in sodium chloride top top their activity sheet.

Give each college student an activity sheet.

Have students compose a brief caption under each picture to explain the process of covalent bonding and answer the very first three questions. The rest of the activity sheet will either it is in completed together a class, in groups, or individually depending upon your instructions.

Project the picture Ionic shortcut in salt chloride.

Review v students the process of ionic bonding extended in the animation.

Help students create a brief caption alongside each photo to define the procedure of ionic bonding in sodium and chloride ions.

Sodium and chlorine atoms are close to each other.The proton of the two atoms attract the electrons of the various other atom. The thicker arrow shows that chlorine has a more powerful attraction for electrons 보다 sodium has.During the interactions between the atoms, the electron in sodium"s outer power level is transferred to the outer energy level that the chlorine atom.Since sodium shed an electron, it has actually 11 protons, but only 10 electrons. This renders sodium a positive ion through a fee of +1. Since chlorine gained an electron it has actually 17 protons and 18 electrons. This provides chloride a negative ion through a charge of −1.The confident sodium ion and negative chloride ion entice one another. They do an ionic bond and kind the ionic link NaCl.Explore

Have students observe actual salt chloride crystals and relate their shape to the molecule model.

This two-part activity will help students see the relationship between the plan of ions in a design of a sodium chloride crystal and also the cubic shape of actual sodium chloride crystals.

Teacher preparation

The day prior to the lesson, dissolve about 10 grams that salt in 50 mL the water. Use Petri dishes or usage scissors to cut down 5 or 6 clean plastic cup to make shallow plastic dishes. Pour enough saltwater to just cover the bottom of each dish (1 for each group). Leaving the bowl overnight to evaporate so that new salt crystals will certainly be produced.

Materials because that each group

Black paperSaltCup v salt from evaporated saltwaterMagnifier permanent marker

Materials because that each student

2 little Styrofoam balls2 large Styrofoam balls2 toothpicks

Procedure, part 1

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

Have students construct a 3-dimensional design of sodium chloride.

Each student will make 1 unit of salt chloride. Students in each group will put their salt chloride systems together. You can help the groups combine their structures right into a course model of a salt chloride crystal.

Procedure, component 2

Make NaCl units.Use the marker to put a “−” top top the huge balls which represent chloride ions.Use the marker to put a “+” top top the tiny balls, which stand for sodium ions.Break two toothpicks in half. Use among the half-toothpicks to attach the centers the the tiny and large ions with each other to make a unit of sodium chloride (NaCl). Carry out the very same thing v the other small and large ball.

Use one more half-toothpick to affix the 2 NaCl devices in a directly line as shown.

Put NaCl ions with each other to do one layer of ions.Contribute your line of ion to her group and also arrange lock to do a 4×4 square of ions.

Use half-toothpicks to attach the end of each line to hold the ions together. Girlfriend only need to ar toothpicks in the balls at the finish of each line.

Build a course sodium chloride crystal.

Give your group’s class of ion to your teacher. Her teacher will certainly stack this to develop a design of a sodium chloride crystal.


Point out that all over you look on the crystal, a sodium ion and also a chloride ion are always surrounded through the oppositely charged ion. This opposite charges hold the ions together in a crystal.


Ask students

Based on the means sodium and chloride ion bond together, why space salt crystals shaped like cubes?The size and also arrangement that the ions forms a cube on the molecular level. Because the sample repeats over and also over again in the very same way, the shape remains the same even when the crystal becomes the normal dimension that we can see.Extend

Show students how calcium and chlorine atoms bond to kind the ionic compound calcium chloride.

Tell students the there is another common substance called calcium chloride (CaCl2). The is the salt the is offered on icy sidewalks and roads. Define that once calcium and chlorine react they create ions, prefer sodium and chlorine, yet the calcium ion is various from the sodium ion.

Ask students:

What ions carry out you think CaCl2 is made of? One calcium ion and also two chloride ions.

Project the animation Calcium chloride Ionic Bond.

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

Some atoms acquire or lose an ext than 1 electron. Calcium loses 2 electrons when it becomes an ion. When ions come with each other to form an ionic bond, they always join in number that exactly cancel out the confident and an adverse charge.

Project the photo Calcium chloride Ionic Bond.

Review v students the procedure of ionic bonding extended in the animation.

Have students write a brief caption in ~ each photo to describe the process of ionic bonding in sodium and also chloride ions.

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One calcium and also two chlorine are near each other.The protons of the calcium atom tempt the electron from the chlorine atom. The protons of the 2 chlorine atoms lure the electrons from the calcium atom much more strongly as displayed by the more thick arrows.During the interactions between the atoms, the two electrons in calcium"s outer power level room transferred come the outer power level of each of the chlorine atoms.Since calcium shed two electrons, it has actually 20 protons, but only 18 electrons. This provides calcium a optimistic ion through a fee of 2+. Because each chlorine atom gained an electron, lock each have actually 17 protons and also 18 electrons. This provides each chloride a negative ion through a fee of −1.Oppositely charged ions lure each other, creating an ionic bond. The bonded ion are much more stable than the individual atom were.