Key Concepts

The attractions between the proloads and electrons of atoms can reason an electron to move totally from one atom to the various other. When an atom loses or gains an electron, it is dubbed an ion. The atom that loses an electron becomes a positive ion.The atom that gains an electron becomes a negative ion.A positive and negative ion entice each various other and form an ionic bond.

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Students will look at animations and also make drawings of the ionic bonding of sodium chloride (NaCl). Students will certainly watch that both ionic and also covalent bonding start via the attractions of prolots and electrons in between various atoms. But in ionic bonding, electrons are moved from one atom to the other and not shared prefer in covalent bonding. Students will usage Styrofoam balls to make models of the ionic bonding in sodium chloride (salt).


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


Downfill the student task sheet, and distribute one per student when mentioned in the task. The task sheet will serve as the “Evaluate” component of each 5-E leschild setup.


Be certain you and the students wear effectively fitting goggles.

Materials for Each Group

Black paperSaltCup via salt from evaporated saltwaterMagnifier Permanent marker

Materials for Each Student

2 small Styrofoam balls2 large Styrofoam balls2 toothpicks

Note: In an ionically bonded substance such as NaCl, the smallest proportion of positive and also negative ions bonded together is referred to as a “formula unit” rather than a “molecule.” Technically speaking, the term “molecule” refers to 2 or even more atoms that are bonded together covalently, not ionically. For simplicity, you could want to use the term “molecule” for both covalently and also ionically bonded substances.


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

Project the animation Ionic bond in sodium chloride.

Remind students that in covalent bonding, atoms share electrons. But there is an additional kind of bonding where atoms don’t share, but instead either take or give up electrons. This is dubbed ionic bonding. This computer animation mirrors a very streamlined design of just how sodium and also chloride ions are created.

Note: In order to simplify the model of ionic bonding, a solitary atom of sodium and also chlorine are shown. In reality, the chlorine atom would be bonded to an additional chlorine atom as part of the gas Cl2. The sodium atom would certainly be among billions of trillions of sodium atoms bonded together as a solid. The combination of these substances is a complex reaction between the atoms of the 2 substances. The animation shows single separated atoms to highlight the concept of how ions and ionic bonds are developed.

Explain what happens in the time of the animation.

Tell students that the attraction of the prolots in the sodium and chlorine for the various other atom’s electrons brings the atoms closer together. Chlorine has a more powerful attraction for electrons than sodium (displayed by the thicker arrow). At some point during this process, an electron from the sodium is moved to the chlorine. The sodium loses an electron and the chlorine gains an electron.

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

Sodium loses an electron, leaving it via 11 proloads, yet only 10 electrons. Due to the fact that it has actually 1 more proton than electrons, sodium has actually a charge of +1, making it a positive ion.Chlorine gains an electron, leaving it with 17 protons and 18 electrons. Due to the fact that it has 1 even more electron than protons, chlorine has actually a charge of −1, making it a negative ion. When ions form, atoms obtain or lose electrons until their outer power level is complete.For example, once sodium loses its one outer electron from the 3rd energy level, the second level becomes the brand-new external energy level and is full. Due to the fact that these electrons are closer to the nucleus, they are more tightly hosted and also will not leave. When chlorine gains an electron, its third energy level becomes complete. An additional electron cannot join, bereason it would must come in at the fourth energy level. This far from the nucleus, the electron would not feel sufficient attractivity from the proloads to be steady. Then the positive sodium ion and also negative chloride ion tempt each other and also form an ionic bond. The ions are more steady when they are bonded than they were as individual atoms.

Have students describe the procedure of ionic bonding in sodium chloride on their task sheet.

Give each student an activity sheet.

Have students write a short caption under each photo to define the procedure of covalent bonding and also answer the initially 3 questions. The rest of the task sheet will certainly either be completed as a class, in groups, or individually relying on your instructions.

Project the picture Ionic bond in sodium chloride.

Resee via students the process of ionic bonding extended in the computer animation.

Aid students compose a brief inscription alongside each picture to explain the procedure of ionic bonding in sodium and also chloride ions.

Sodium and also chlorine atoms are near each other.The prolots of the 2 atoms tempt the electrons of the other atom. The thicker arrowhead shows that chlorine has a stronger attraction for electrons than sodium has actually.During the interactions between the atoms, the electron in sodium"s outer energy level is moved to the external energy level of the chlorine atom.Due to the fact that sodium shed an electron, it has actually 11 protons, however just 10 electrons. This makes sodium a positive ion via a charge of +1. Because chlorine acquired an electron it has 17 protons and 18 electrons. This makes chloride an adverse ion via a charge of −1.The positive sodium ion and also negative chloride ion attract one another. They make an ionic bond and create the ionic compound NaCl.Explore

Have students observe actual sodium chloride crystals and relate their form to the molecular version.

This two-component task will aid students view the relationship in between the arrangement of ions in a version of a sodium chloride crystal and the cubic shape of genuine sodium chloride crystals.

Teacher preparation

The day prior to the lesboy, dissolve around 10 grams of salt in 50 mL of water. Use Petri dishes or use scissors to reduced down 5 or 6 clear plastic cups to make shenable plastic dishes. Pour enough saltwater to just cover the bottom of each dish (1 for each group). Leave the dishes overnight to evapoprice so that brand-new salt crystals will certainly be created.

Materials for each group

Black paperSaltCup via salt from evaporated saltwaterMagnifier Permanent marker

Materials for each student

2 small Styrofoam balls2 large Styrofoam balls2 toothpicks

Procedure, Part 1

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

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

Each student will certainly make 1 unit of sodium chloride. Students in each team will certainly put their sodium chloride units together. You deserve to help the teams combine their structures right into a class design of a sodium chloride crystal.

Procedure, Part 2

Make NaCl units.Use the marker to put a “−” on the big balls which recurrent chloride ions.Use the marker to put a “+” on the tiny balls, which represent sodium ions.Break two toothpicks in half. Use among the half-toothpicks to connect the centers of the little and big ions together to make a unit of sodium chloride (NaCl). Do the exact same thing via the various other small and big ball.

Use an additional half-toothpick to affix the 2 NaCl systems in a directly line as displayed.

Put NaCl ions together to make one layer of ions.Contribute your line of ions to your team and ararray them to make a 4×4 square of ions.

Use half-toothpicks to attach the ends of each line to organize the ions together. You just must location toothpicks in the balls at the finish of each line.

Build a class sodium chloride crystal.

Give your group’s layer of ions to your teacher. Your teacher will stack these to construct a version of a sodium chloride crystal.


Point out that all over you look on the crystal, a sodium ion and also a chloride ion are constantly surrounded by the oppositely charged ion. These opposite charges host the ions together in a crystal.


Ask students

Based on the means sodium and also chloride ions bond together, why are salt crystals shaped like cubes?The dimension and also plan of the ions creates a cube on the molecular level. Since the pattern repeats over and also over aget in the exact same method, the form stays the same even as soon as the crystal becomes the normal dimension that we deserve to see.Extend

Sjust how students how calcium and chlorine atoms bond to create the ionic compound calcium chloride.

Tell students that there is another widespread substance dubbed calcium chloride (CaCl2). It is the salt that is used on icy sidewalks and roads. Exordinary that as soon as calcium and chlorine react they create ions, favor sodium and chlorine, however 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 2 chloride ions.

Project the computer animation Calcium chloride Ionic Bond.

Point out that the calcium loses 2 electrons, becoming a +2 ion. Each of the two chlorine atoms gains among these electrons, making them each a −1 ion. Aid students realize that 1 calcium ion bonds through 2 chloride ions to form calcium chloride (CaCl2), which is neutral.

Some atoms obtain or shed more than 1 electron. Calcium loses 2 electrons once it becomes an ion. When ions come together to create an ionic bond, they always sign up with in numbers that precisely cancel out the positive and also negative charge.

Project the image Calcium chloride Ionic Bond.

Resee with students the procedure of ionic bonding covered in the computer animation.

Have students compose a brief inscription beneath each picture to define the procedure of ionic bonding in sodium and also chloride ions.

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One calcium and 2 chlorine are close to each other.The protons of the calcium atom entice the electrons from the chlorine atom. The protons of the 2 chlorine atoms attract the electrons from the calcium atom even more strongly as presented by the thicker arrows.During the interactions between the atoms, the 2 electrons in calcium"s outer power level are moved to the external power level of each of the chlorine atoms.Due to the fact that calcium shed two electrons, it has 20 proloads, but only 18 electrons. This makes calcium a positive ion via a charge of 2+. Due to the fact that each chlorine atom acquired an electron, they each have 17 protons and also 18 electrons. This renders each chloride a negative ion with a charge of −1.Oppositely charged ions lure each other, forming an ionic bond. The bonded ions are more stable than the individual atoms were.