Standard 3d Preknowledge
3d) Students know salt crystals, such as NaCl, are repeating patterns of positive and negative ions held together by electrostatic attraction.
CALIFORNIA FRAMEWORKS SUMMARY: The energy that holds ionic compounds together, called lattice energy, is caused by the electrostatic attraction of cations, which are positive ions, with anions, which are negative ions. To minimize their energy state, the ions form repeating patterns that reduce the distance between positive and negative ions and maximize the distance between ions of like charges.