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The Structure of Matter
Each of the more than 100 elements of matter has distinct properties and a distinct atomic structure. All forms of matter are composed of one or more of the elements. As a basis for understanding this concept students should know :
- the structure of the atom and how it is composed of protons, neutrons, and electrons.
- compounds are formed by combining two or more different elements and that compounds have properties that are different from their constituent elements.
- atoms and molecules form solids by building up repeating patterns, such as the crystal structure of NaCl or long-chain polymers.
- the states of matter (solid, liquid, gas) depend on molecular motion.
- in solids the atoms are closely locked in position and can only vibrate; in liquids the atoms and molecules are more loosely connected and can collide with and move past one another; and in gases the atoms and molecules are free to move independently, colliding frequently.
- how to use the periodic table to identify elements in simple compounds.
- how to identify regions corresponding to metals, nonmetals, and inert gases.
- each element has a specific number of protons in the nucleus (the atomic number) and each isotope of the element has a different but specific number of neutrons in the nucleus.
- substances can be classified by their properties, including their melting temperature, density, hardness, and thermal and electrical conductivity.
- reactant atoms and molecules interact to form products with different chemical properties.
- the idea of atoms explains the conservation of matter: in chemical reactions the number of atoms stays the same no matter how they are arranged, so their total mass stays the same.
- chemical reactions usually liberate heat or absorb heat.
- physical processes include freezing and boiling in which a material changes form with no chemical reaction.
- how to determine whether a solution is acidic, basic or neutral.
The Chemistry of Living Things
Principles of chemistry underlie the functioning of biological systems. As a basis for understanding this concept students know:- that carbon, because of its ability to combine in many ways with itself and other elements, has a central role in the chemistry of living organism.
- that living organisms are made of molecules consisting largely of carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur.
- that living organisms have many different kinds of molecules including small ones, such as water and salt, and very large ones, such as carbohydrates, fats, proteins, and DNA.