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SOL 6.5 Atoms, Elements, compounds (New 2018 standards)
    The student will investigate and understand that all matter is made up of atoms. Key concepts include
  1. atoms consist of particles, including electrons, protons, and neutrons
  2. atoms of a particular element are similar but differ from atoms of other elements;
  3. elements may be represented by chemical symbols;
  4. two or more atoms interact to form new substances, which are held together by electrical forces (bonds);
  5. compounds may be represented by chemical formulas
  6. chemical equations can be used to model chemical changes
  7. a few elements comprise the largest portion of the solid Earth, living matter, the oceans, and the atmosphere

Central Idea: Atoms are the basic building blocks of all matter.

Atomic Structure

Atoms are the basic building blocks of all matter. The properties of an atom are based on the number and arrangement of its subatomic particles.

  • The basic structural components of a typical atom are electrons, protons, and neutrons. 
    • Protons and neutrons comprise the nucleus of an atom.
  • An element is a form of matter made up of one type of atom.
  •  The atoms of an element have the same number of protons and electrons, although the number of neutrons may vary.

  • The atoms of one element differ from those of another element in the number of protons.
  • Elements can be represented by chemical symbols.
Compounds and Chemical Equations

In a chemical process, the atoms that make up the original substance (reactants) are regrouped into different molecules and the new substances (products) have different properties from the properties of the reactants.

  • Two or more atoms of different elements may combine to form a compound.
  • Chemical bonds are the forces that hold atoms together to form new substances. 
    • These bonds are formed with electrons.
  • Compounds can be represented by chemical formulas. 
    • Each element in the compound is represented by its unique symbol. 
    • The number of each type of element in the compound (other than one) is represented by a small number (the subscript) to the right of the element symbol
  • Matter is conserved because atoms are conserved in chemical and physical processes.
  • Chemical equations can be used to model chemical changes, illustrating how elements become rearranged in a chemical reaction.
Elements forming Earth, Life, and Oceans
  • A limited number of elements form the largest portion of Earth’s crust, living matter, the oceans, and the atmosphere.
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