Key concepts

The attractions in between the protons and electrons of atoms can cause an electron to move totally from one atom to the other. Once an atom loses or gains an electron, the is dubbed an ion. The atom the loses an electron becomes a hopeful ion.The atom the gains an electron becomes a an unfavorable ion.A confident and an unfavorable ion entice each other and kind an ionic bond.

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Students will look in ~ animations and make illustrations of the ionic bonding of salt chloride (NaCl). College student will watch that both ionic and also covalent bonding start with the attractions that protons and electrons in between different atoms. However in ionic bonding, electrons space transferred indigenous one atom to the other and not common like in covalent bonding. Students will use 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 per student as soon as specified in the activity. The activity sheet will serve together the “Evaluate” ingredient of every 5-E great plan.


Be sure you and the student wear properly fitting goggles.

Materials for Each Group

Black paperSaltCup v salt from evaporated saltwaterMagnifier permanent marker

Materials for Each Student

2 little Styrofoam balls2 big Styrofoam balls2 toothpicks

Note: In one ionically external inspection substance such together NaCl, the smallest ratio of optimistic and an unfavorable ions bonded with each other is called a “formula unit” quite than a “molecule.” Technically speaking, the ax “molecule” refers to two or an ext atoms that space bonded with each other covalently, no ionically. Because that simplicity, you might want to usage the term “molecule” because that both covalently and also ionically external inspection substances.


Show an animation to present the process of ionic bonding.

Project the computer animation Ionic bond in salt chloride.

Remind students the in covalent bonding, atom share electrons. However there is another kind of bonding wherein atoms don’t share, however instead either take it or give up electrons. This is called ionic bonding. This computer animation shows a very simplified model of exactly how sodium and chloride ions room formed.

Note: In order to leveling the design of ionic bonding, a single atom the sodium and also chlorine room shown. In reality, the chlorine atom would be external inspection to one more chlorine atom as component of the gas Cl2. The salt atom would be one of billions that trillions of salt atoms bonded together as a solid. The mix of this substances is a complicated reaction between the atom of the two substances. The computer animation shows single separated atoms to highlight the idea of just how ions and also ionic bonds are formed.

Explain what happens during the animation.

Tell students that the attraction that the protons in the sodium and chlorine because that the other atom’s electrons bring the atoms closer together. Chlorine has a more powerful attraction because that electrons than sodium (shown by the thicker arrow). In ~ some suggest during this process, an electron indigenous the sodium is moved to the chlorine. The sodium loses an electron and the chlorine benefit an electron.

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

Sodium loser an electron, leaving it v 11 protons, but only 10 electrons. Due to the fact that it has actually 1 an ext proton 보다 electrons, sodium has a charge of +1, making the a confident ion.Chlorine profit an electron, leave it through 17 protons and also 18 electrons. Due to the fact that it has actually 1 more electron 보다 protons, chlorine has actually a fee of −1, making the a an unfavorable ion. As soon as ions form, atoms acquire or lose electrons till their outer power level is full.For example, as soon as sodium loser its one external electron native the 3rd energy level, the 2nd level becomes the new outer power level and is full. Because these electrons space closer to the nucleus, castle are much more tightly held and also will not leave. Once chlorine profit an electron, its third energy level i do not care full. An additional electron can not join, because it would need to come in in ~ the fourth power level. This much from the nucleus, the electron would not feel enough attraction indigenous the protons to be stable. Then the hopeful sodium ion and negative chloride ion entice each various other and type an ionic bond. The ion are an ext stable when they room bonded 보다 they were as individual atoms.

Have students describe the procedure of ionic bonding in salt chloride ~ above their task sheet.

Give each student an task sheet.

Have students compose a short caption under each photo to explain the process of covalent bonding and also answer the first three questions. The rest of the activity sheet will either it is in completed together a class, in groups, or individually relying on your instructions.

Project the picture Ionic link in salt chloride.

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

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

Sodium and chlorine atom are close to each other.The proton of the 2 atoms lure the electron of the various other atom. The thicker arrowhead shows the chlorine has a stronger attraction for electrons 보다 sodium has.During the interactions in between the atoms, the electron in sodium"s outer energy level is moved to the outer power level of the chlorine atom.Since sodium shed an electron, it has actually 11 protons, yet only 10 electrons. This renders sodium a positive ion with a charge of +1. Since chlorine acquired an electron it has 17 protons and 18 electrons. This renders chloride a negative ion with a charge of −1.The confident sodium ion and an adverse chloride ion attract one another. They do an ionic link and form the ionic compound NaCl.Explore

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

This two-part task will assist students view the relationship in between the arrangement of ions in a model of a salt chloride crystal and also the cubic shape of real sodium chloride crystals.

Teacher preparation

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

Materials for each group

Black paperSaltCup v salt native evaporated saltwaterMagnifier long-term marker

Materials for each student

2 small Styrofoam balls2 big Styrofoam balls2 toothpicks

Procedure, component 1

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

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

Each student will certainly make 1 unit of sodium chloride. Student in each group will placed their salt chloride systems together. Girlfriend can aid the groups integrate their structures right into a class model that a sodium 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 “+” on the small balls, which represent sodium ions.Break 2 toothpicks in half. Use one of the half-toothpicks to connect the centers the the little and huge ions together to make a unit of sodium chloride (NaCl). Perform the very same thing with the other tiny and large ball.

Use another half-toothpick to attach the two NaCl units in a straight line as shown.

Put NaCl ions together to make one layer of ions.Contribute her line of ions to her group and also arrange lock to make a 4×4 square the ions.

Use half-toothpicks to attach the end of every line to organize the ion together. Friend only need to ar toothpicks in the balls at the finish of every line.

Build a class sodium chloride crystal.

Give her group’s great of ions to her teacher. Your teacher will certainly stack this to develop a model of a sodium chloride crystal.


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


Ask students

Based top top the means sodium and chloride ion bond together, why are salt crystals shaped favor cubes?The size and also arrangement that the ions creates a cube on the molecular level. Due to the fact that the sample repeats over and over again in the exact same way, the shape remains the same also when the decision becomes the normal size that we deserve to see.Extend

Show students exactly how calcium and also chlorine atoms bond to kind the ionic link calcium chloride.

Tell students the there is one more common substance called calcium chloride (CaCl2). That is the salt that is offered on icy sidewalks and also roads. Explain that as soon as calcium and also chlorine reaction they produce ions, choose sodium and also chlorine, but the calcium ion is different from the salt ion.

Ask students:

What ions perform you think CaCl2 is do 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, make them each a −1 ion. Assist students realize that 1 calcium ion bonds through 2 chloride ions to type calcium chloride (CaCl2), which is neutral.

Some atoms obtain or lose much more than 1 electron. Calcium loser 2 electrons once it i do not care an ion. As soon as ions come together to type an ionic bond, they always join in numbers that specifically cancel out the optimistic and an adverse charge.

Project the picture Calcium chloride Ionic Bond.

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

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

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One calcium and two chlorine are close to each other.The protons of the calcium atom entice the electrons from the chlorine atom. The protons of the two chlorine atoms entice the electrons from the calcium atom more strongly as shown by the thicker arrows.During the interactions between the atoms, the 2 electrons in calcium"s outer power level space transferred come the outer energy level of each of the chlorine atoms.Since calcium shed two electrons, it has actually 20 protons, yet only 18 electrons. This provides calcium a optimistic ion through a charge of 2+. Since each chlorine atom acquired an electron, lock each have 17 protons and 18 electrons. This provides each chloride a negative ion through a fee of −1.Oppositely charged ions attract each other, creating an ionic bond. The bonded ions are much more stable 보다 the individual atoms were.