Na CI atoms bonding

Modeling Ionic Bonding of Atoms with the AZER APH Model

This activity focuses on ionic bonding and the importance of valence electrons in chemical bonding.

This activity uses the excellent AZER atom model to depict ionic bonding of sodium and chloride forming table salt. It should be part of instruction on chemical bonding and the use of other examples of chemical bonding could also be used. 

Related Vocabulary:



The image is of a sodium atom.
Sodium atom
The image is of a chlorine atom.
Chlorine atom


This activity should be appropriate after the structure of the atom has been covered thoroughly and valence electrons introduced.

Students should also have been introduced to the APH Azer model prior to this activity and should understand the varying sizes and tactile surfaces used for 1,5 and 10 neutrons or protons. See instructions to the model.

  1. Pass out a Cl atom to one student and a Na atom to a second student. 
  2. Remind students of recent discussion of bonding and valence electrons and discuss.
  3. Have students look at their atoms and their neighbors atoms. As shown.   Ask – Which electrons in the atom are closest to the electrons of your neighbors atom? Discuss valence electrons and bonding. The electrons closes to the other atom are those which affect bonding – e.g. the electrons on the outer electron level or valence electrons.    
The image is of a Cl and Na atom.
Sodium and Chloride atoms after bonding has occurred
  1. Have students determine the number of valence electrons of the atom which he/she was given and then have students switch with their neighbor.
  2. Determine the number of valence electrons again.  
  3. Remind students that the 2nd and 3rd levels of electrons are full with 8 electrons.
  4. Ask students whether either of the atoms has 8 electrons in the outer level. Students should notice that neither does and that Na has only 1 and that Cl has 7.
  5. Ask – Will it be easier for Na to give up 1 or gain 7 to have a full outer layer? Students should respond that it will be easier to give up one.
  6. Ask – Will it be easier for Cl to give up 7 or gain 1 in order to have a full outer layer? Students should respond that it will be easier to gain one. 
  7. Have the students with Cl “steal” one electron from the outer level of the Na atom. As shown.
  1. Again ask students whether the outer electron level in each atom is full. Yes
  2. Discuss ionic bonding in more detail after the activity Ionic bonding of atoms occurs when one atom effectively “steals” one or more electrons from another atom to become more stable. 


The activity is described for 2 students but can be adapted for one by having the instructor play the “neighbor” as per the the procedure. 

NGSS Standards

High School Physical Science
PS1.A: Structure and Properties of Matter

PS2.B: Types of Interactions

By Laura Hospitál

Collage of modeling ionic bonding of atoms

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