How Water Conducts Electricity: Chemistry A Lesson Cycle 2
In Chemistry, we learn about what is happening at the molecular and atomic levels to explain more visible phenomena. Lesson Cycle 2 asks a puzzling question: how does saltwater conduct electricity? This question can be applied to a number of important issues in our lives, but one we will all likely deal with at one point or another is dropping our beloved cellphone in water. In this module, we will explore how and why different water solutions, including saltwater, sugar water, or distilled water, are more likely to conduct electricity (and therefore cause irreparable harm to your phone!). In order to truly understand what is at play, we must look at salt, sugar, and water at the molecular and atomic levels to see how they are formed and how their properties differ. Chemistry topics addressed in this module include the parts of an atom, electron shells or energy levels, valence electrons, electron dot diagrams, the octet rule, and types of chemical bonds.
By engaging in this module, teachers will gain the following knowledge, skills, and mindsets in pursuit of reaching Teach for America's Vision for Learning in Secondary Science:
- Teachers will understand and be able to explain that the periodic table is arranged in groups and periods; that atoms in the same group have the same number of valence electrons; and that atoms in the same period have the same number of electron shells.
- Teachers will understand that the number of valence electrons an atom has will determine its properties, including how it reacts to or bonds with other atoms.
- Teachers will be able to explain the differences in the bonds and valence electrons for salt and water (NaCl electrons are transferred, forms a lattice structure, whereas in water the electrons are shared, forms a polar molecule).
- Teachers will be able to identify and describe the arrangement of electrons in the outermost energy level of atoms (ie, valence electrons) using the periodic table.
- Teachers are able to complete electron shell (Bohr) models for various atoms, and identify patterns in the outer shell, constructing the concept of valence electrons.
- Teachers will be able to use the periodic table to predict patterns in the number and charges in stable ions that form from atoms in a group of the periodic table based on the patterns of outermost electrons.
- Teachers will be able to construct Lewis dot structures to model the structure of substances with covalent and ionic bonds.
- Teachers believe that all students deserve the right to develop a deep understanding of science as a way of knowing, in order to become both confident consumers and producers of scientific knowledge, and develop agency to drive improvements in the local and global community through the application of science and technology.