Key ideas

The attractions between the protons and electrons of atom can cause an electron to move totally from one atom come the other. As soon as an atom loses or benefit an electron, the is referred to as an ion. The atom that loses an electron becomes a optimistic ion.The atom that gains an electron becomes a negative ion.A optimistic and an adverse ion lure each other and form an ionic bond.

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Students will certainly look at animations and also make drawings of the ionic bonding of salt chloride (NaCl). College student will check out that both ionic and covalent bonding begin with the attractions of protons and electrons in between different atoms. But in ionic bonding, electrons room transferred from one atom to the other and also not shared like in covalent bonding. Students will usage Styrofoam balls to do models that the ionic bonding in sodium chloride (salt).


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


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


Be sure you and also the students wear correctly fitting goggles.

Materials because that Each Group

Black paperSaltCup through salt indigenous evaporated saltwaterMagnifier permanent marker

Materials for Each Student

2 small Styrofoam balls2 big Styrofoam balls2 toothpicks

Note: In an ionically bonded substance such as NaCl, the smallest ratio of confident and negative ions bonded together is called a “formula unit” fairly than a “molecule.” Technically speaking, the term “molecule” refers to two or much more atoms that are bonded together covalently, no ionically. For simplicity, you could want to use the term “molecule” because that both covalently and also ionically external inspection substances.


Show an animation to introduce the process of ionic bonding.

Project the animation Ionic bond in salt chloride.

Remind students the in covalent bonding, atom share electrons. However there is another kind of bonding where atoms don’t share, but instead either take it or offer up electrons. This is called ionic bonding. This animation shows a really simplified version of exactly how sodium and chloride ions space formed.

Note: In bespeak to simplify the version of ionic bonding, a single atom the sodium and also chlorine space shown. In reality, the chlorine atom would certainly be external inspection to an additional chlorine atom as part of the gas Cl2. The salt atom would certainly be among billions that trillions of sodium atoms bonded together as a solid. The mix of this substances is a complicated reaction 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 during the animation.

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

Tell students that once an atom profit or loses an electron, it becomes an ion.

Sodium loser an electron, leaving it through 11 protons, but only 10 electrons. Because it has 1 much more proton than electrons, sodium has actually a charge of +1, making the a optimistic ion.Chlorine gains an electron, leaving it v 17 protons and also 18 electrons. Since it has actually 1 an ext electron 보다 protons, chlorine has actually a fee of −1, making that a an adverse ion. Once ions form, atoms gain or shed electrons till their outer energy level is full.For example, when sodium loses its one outer electron indigenous the third energy level, the 2nd level becomes the new outer power level and also is full. Since these electrons are closer come the nucleus, castle are an ext tightly held and also will not leave. Once chlorine gains an electron, its third energy level i do not care full. An additional electron can not join, due to the fact that it would must come in at the fourth energy level. This much from the nucleus, the electron would not feel sufficient attraction from the protons to be stable. Then the confident sodium ion and negative chloride ion lure each other and form an ionic bond. The ion are more stable as soon as they are bonded than they were as individual atoms.

Have students define the process of ionic bonding in salt chloride top top their activity sheet.

Give each student an task sheet.

Have students create a short caption under each photo to define the procedure of covalent bonding and answer the very first three questions. The remainder of the task sheet will either be completed together a class, in groups, or individually depending on your instructions.

Project the image Ionic bond in salt chloride.

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

Help students write a quick caption beside each picture to describe the process of ionic bonding in sodium and chloride ions.

Sodium and also chlorine atoms are close to each other.The protons of the two atoms attract the electrons of the various other atom. The thicker arrow shows the chlorine has a more powerful attraction for electrons than sodium has.During the interactions in between the atoms, the electron in sodium"s outer energy level is transferred to the outer power level that the chlorine atom.Since sodium shed an electron, it has actually 11 protons, yet only 10 electrons. This makes sodium a hopeful ion with a fee of +1. Because chlorine gained an electron it has actually 17 protons and also 18 electrons. This provides chloride a an adverse ion through a fee of −1.The hopeful sodium ion and an unfavorable chloride ion attract one another. They do an ionic link and kind the ionic compound NaCl.Explore

Have students watch actual sodium chloride crystals and also relate their shape to the molecular model.

This two-part task will help students see the relationship in between the plan of ions in a model of a sodium chloride crystal and also the cubic form of genuine sodium chloride crystals.

Teacher preparation

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

Materials because that each group

Black paperSaltCup with salt native evaporated saltwaterMagnifier long-term marker

Materials for each student

2 small Styrofoam balls2 big Styrofoam balls2 toothpicks

Procedure, part 1

Observe sodium chloride crystals.Place a few grains that salt ~ above a piece of black color paper. Usage your magnifier to look very closely at the salt.

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

Each student will certainly make 1 unit of salt chloride. Student in each group will put their salt chloride devices together. Girlfriend can assist the groups incorporate their structures right into a class model that a salt chloride crystal.

Procedure, part 2

Make NaCl units.Use the marker to placed a “−” ~ above the huge balls which stand for chloride ions.Use the mite to placed a “+” ~ above the little balls, which stand for sodium ions.Break 2 toothpicks in half. Use one of the half-toothpicks to connect the centers that the little and big ions with each other to make a unit of sodium chloride (NaCl). Perform the same thing through the other little and huge ball.

Use an additional half-toothpick to connect the 2 NaCl systems in a right line as shown.

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

Use half-toothpicks to affix the end of each line to hold the ion together. You only require to ar toothpicks in the balls in ~ the finish of each line.

Build a course sodium chloride crystal.

Give her group’s layer of ions to your teacher. Your teacher will certainly stack these to build a design of a sodium chloride crystal.


Point the end that everywhere you look on the crystal, a sodium ion and a chloride ion are always surrounded through the oppositely charged ion. These opposite charges host the ions together in a crystal.


Ask students

Based ~ above the means sodium and chloride ion bond together, why are salt crystals shaped favor cubes?The size and also arrangement that the ions forms a cube on the molecule level. Because the pattern repeats over and also over again in the same way, the shape continues to be the same even when the crystal becomes the normal dimension that we can see.Extend

Show students exactly how calcium and chlorine atom bond to form the ionic link calcium chloride.

Tell students the there is another common substance referred to as calcium chloride (CaCl2). That is the salt the is offered on icy sidewalks and also roads. Describe that when calcium and also chlorine reaction they create ions, like sodium and chlorine, yet the calcium ion is different from the sodium ion.

Ask students:

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

Project the computer animation Calcium chloride Ionic Bond.

Point the end that the calcium loses two electrons, coming to be a +2 ion. Every of the 2 chlorine atom gains one of these electrons, do them each a −1 ion. Aid students realize that 1 calcium ion bonds through 2 chloride ion to kind calcium chloride (CaCl2), i beg your pardon is neutral.

Some atoms gain or lose much more than 1 electron. Calcium loses 2 electrons when it i do not care an ion. As soon as ions come together to form an ionic bond, they constantly join in numbers that specifically cancel the end the optimistic and an unfavorable charge.

Project the photo Calcium chloride Ionic Bond.

Review with students the procedure of ionic bonding covered in the animation.

Have students compose a quick caption in ~ each picture to define the process of ionic bonding in sodium and chloride ions.

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One calcium and two chlorine are near each other.The protons of the calcium atom entice the electrons from the chlorine atom. The proton of the 2 chlorine atoms tempt the electron from the calcium atom much more strongly as displayed by the more thick arrows.During the interactions in between the atoms, the 2 electrons in calcium"s outer energy level room transferred to the outer energy level of every of the chlorine atoms.Since calcium lost two electrons, it has actually 20 protons, however only 18 electrons. This renders calcium a positive ion through a fee of 2+. Because each chlorine atom got an electron, lock each have actually 17 protons and 18 electrons. This provides each chloride a negative ion v a fee of −1.Oppositely fee ions tempt each other, developing an ionic bond. The bonded ion are more stable 보다 the individual atoms were.