Defining the system under study—specifying its boundaries and making explicit a model of that system—provides tools for understanding and testing ideas that are applicable throughout science and engineering.
Cause and Effect
Mechanism and explanation. Events have causes, sometimes simple, sometimes multifaceted. A major activity of science is investigating and explaining causal relationships and the mechanisms by which they are mediated. Such mechanisms can then be tested across given contexts and used to predict and explain events in new contexts.
Science & Engineering Practices
Constructing Explanations and Designing Solutions
The goal of science is the construction of theories that provide explanatory accounts of the world. A theory becomes accepted when it has multiple lines of empirical evidence and greater explanatory power of phenomena than previous theories.”(NRC Framework, 2012, p. 52)
Generating a Hypothesis and Developing a Model
Modeling can begin in the earliest grades, with students’ models progressing from concrete “pictures” and/or physical scale models (e.g., a toy car) to more abstract representations of relevant relationships in later grades, such as a diagram representing forces on a particular object in a system. (NRC Framework, 2012, p. 58)
Planning and Carrying Out Investigations
Students should have opportunities to plan and carry out several different kinds of investigations during their K-12 years. At all levels, they should engage in investigations that range from those structured by the teacher—in order to expose an issue or question that they would be unlikely to explore on their own (e.g., measuring specific properties of materials)— to those that emerge from students’ own questions. (NRC Framework, 2012, p. 61)
adhesion - the tendency of molecules to stick to substances that are dissimilar.
anion - a negatively charged ion.
cation - a positively charged ion.
chemical bond - an electrical interaction between the positively charged nuclei and the negatively charged electrons of atoms that forms when the force of attraction is stronger than the force of repulsion.
cohesion - the action or property of like molecules sticking together, being mutually attractive.
covalent bond - a bond in which pairs of electrons are shared between atoms, instead of being transferred from one atom to another.
double covalent bond - a bond in which atoms share two pairs of electrons.
electronegativity - the ability of an atom to attract additional electrons.
electrostatic force - a force in which oppositely charged particles are attracted to each other, while like charges repel each other.
intermolecular forces - the attractive forces acting between molecules.
intramolecular bond - a bond that is occuring within a molecule.
ion - an atom with a positive or negative charge.
ionic bond - a bond that occurs between atoms, through the transfer of electrons, when a positively charged atom and negatively charged atom are attracted to one another.
molecule - a group of atoms that have chemically bonded and behave as an individual unit.
nonpolar covalent bond - a bond that forms between atoms in which their electrons are shared equally.
octet rule - when an ion or an atom has eight valence electrons, it is at its most stable electron configuration.
polar covalent bond - a bond in which electrons are shared unequally between atoms.
single covalent bond - a bond in which atoms share only one pair of electrons.
triple covalent bond - A bond in which atoms share three pairs of electrons.
valence electrons - the electrons found in the outermost electron shell of an atom.
Georgia Standards of Excellence
SC2Obtain, evaluate, and communicate information about the chemical and physical properties of matter resulting from the ability of atoms to form bonds.
SC2.aPlan and carry out an investigation to gather evidence to compare the physical and chemical properties at the macroscopic scale to infer the strength of intermolecular and intramolecular forces.
SC2.bConstruct an argument by applying principles of inter- and intra- molecular forces to identify substances based on chemical and physical properties.
SC2.dDevelop and use models to evaluate bonding configurations from nonpolar covalent to ionic bonding. (Clarification statement: VSEPR theory is not addressed in this element.)
SPS2Obtain, evaluate, and communicate information to explain how atoms bond to form stable compounds.
SPS2.aAnalyze and interpret data to predict properties of ionic and covalent compounds. (Clarification statement: Properties are limited to types of bonds formed, elemental composition, melting point, boiling point, and conductivity.)
Request Teacher Toolkit
The Chemistry Matters teacher toolkit provides instructions and answer keys for labs, experiments, and assignments for all 12 units of study. GPB offers the teacher toolkit at no cost to Georgia educators. Complete and submit this form to request the teacher toolkit. You only need to submit this form one time to get materials for all 12 units of study.