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Knowledge and Skills Statement

Matter and energy. The student knows that matter is made of atoms, can be classified according to its properties, and can undergo changes.

Matter can be understood in terms of the types of particles present and the interactions both between and within them. The states (i.e., solid, liquid, gas, or plasma), properties (e.g., hardness, conductivity), and reactions (both physical and chemical) of matter can be described and predicted based on the types, interactions, and motions of the atoms within it. 

the smallest particle of matter that has distinct physical and chemical properties; consists of a nucleus which contains protons and neutrons and an electron cloud which contains electrons

a material which consists of multiple different substances that are not evenly distributed; each sample of the mixture may have different proportions of the individual components

 a material which consists of multiple different substances that are evenly distributed; each sample of the mixture will have the same proportion of the individual components

substance that occupies space, has mass, and is composed of microscopic particles

a group of atoms that are chemically bonded to each other

observable characteristics of matter that can be used to identify particular materials

observable characteristics of matter that can be used to identify particular materials

material that is made of a single element or compound; every particle of a substance is the same type of atom or molecule

a substance in which a solid, liquid, or gaseous substance is evenly distributed (or dissolved) within a liquid or sometimes a gas or solid

Research

Yakmaci-Guzel, Buket, and Emine Adadan. "Use of Multiple Representations in Developing Preservice Chemistry Teachers' Understanding of the Structure of Matter." International Journal of Environmental and Science Education 8, no. 1 (2013): 109-130. https://files.eric.ed.gov/fulltext/EJ1008597.pdf.

Summary: Using a study on preservice chemistry teachers, the article "Use of Multiple Representations in Developing Preservice Chemistry Teachers' Understanding of the Structure of Matter" helps clarify what constitutes a homogeneous and heterogeneous mixture.  Understanding is developed through a hands-on activity using paper clips to represent particles of elements, compounds, and mixtures.