Classify each statement as an observation, a law, or a theory. a. Chlorine is a highly reactive gas. b. If elements are listed in order of increasing mass of their atoms, their chemical reactivities follow a repeating pattern. c. Neon is an inert (or nonreactive) gas. d. The reactivity of elements depends on the arrangement of their electrons.

Verified step by step guidance

1. Identify the definition of an observation: An observation is a statement based on something that is seen, heard, or noticed.
2. Identify the definition of a law: A law is a statement that describes an observable occurrence in nature that appears to always be true.
3. Identify the definition of a theory: A theory is a well-substantiated explanation of some aspect of the natural world that is based on a body of evidence and has been repeatedly confirmed through observation and experimentation.
4. Classify statement (a) 'Chlorine is a highly reactive gas' as an observation because it describes a characteristic of chlorine that can be directly observed.
5. Classify statement (b) 'If elements are listed in order of increasing mass of their atoms, their chemical reactivities follow a repeating pattern' as a law because it describes a consistent and repeatable pattern observed in nature, known as the periodic law.

Key Concepts

Observation

An observation is a statement based on direct evidence or sensory experience. It describes a specific phenomenon without attempting to explain why it occurs. For example, stating that 'Chlorine is a highly reactive gas' is an observation because it reports a characteristic of chlorine based on empirical evidence.

Law

A law is a concise statement that describes a consistent relationship observed in nature, often expressed mathematically. Laws summarize patterns found in data and are universally applicable under specified conditions. The statement 'If elements are listed in order of increasing mass of their atoms, their chemical reactivities follow a repeating pattern' exemplifies a law, as it describes a predictable trend in chemical behavior.

Theory

A theory is a well-substantiated explanation of an aspect of the natural world that is based on a body of evidence and can be tested through experimentation. The statement 'The reactivity of elements depends on the arrangement of their electrons' represents a theory, as it provides an explanation for chemical reactivity based on the underlying principles of atomic structure and electron configuration.