There are several different chemical bonds found in nature. Ionic bonding represents the attraction of cations (positively charged ions) to anions (negatively charged ions). There is a strong electrostatic interaction between these oppositely charged ions, which forms a bond that requires the input of energy to break. One consequence of this high level of electrostatic attraction is the high boiling point of molecules with ionic bonds.
Ionic bonding commonly generates lattices, in which the components of that lattice alternate with each other in three-dimensional space. Common table salt, NaCl, is an example of a lattice generated through ionic bonding between sodium ions (positively charged) and chloride ions (negatively charged). Sodium has a single electron in its valence shell while chloride has seven electrons in its outer valence shell. An ionic bond occurs when one atom "steals" an electron from another atom and in so doing, allows for each valence shell to be complete. Visualizing the repeating pattern found in salt lattices is often challenging for students. Through the models in this collection, the crystal shape of salt is easily seen and manipulated.
This collection also includes models of water, so that the concept of solubility can be explored. The ionic bond between sodium and chloride is easily dissociated in water as water will interact readily with the ions. Through the use of these models, a student can examine how many water molecules are needed to dissolve a single NaCl ionic bond. The concept of saturation can also be discussed with reference to the availability of water to interact with NaCl molecules.
Teaching Points and Inventory
NaCl Science Activities Teacher Notes
Patterns in Crystal Structures Teacher Notes
Patterns in Crystal Structures Student Handouts
Patterns in Crystal Structures Teacher Kay
Models must be returned on or before the due date. Borrowers are responsible for return shipping costs.
Ship models to:
Milwaukee School of Engineering
1000 N. Market Street
Milwaukee, WI 53202-3113
Please insure the models for the amount indicated in each suitcase. Any damage incurred in return shipping due to improper packing will be charged to the borrower. We recommend using FedEx or UPS with "two-day ground" transportation. Make sure to get a tracking number for the shipment.