7.6.A:  compare and contrast elements and compounds in terms of atoms and molecules, chemical symbols, and chemical formulas;

Compare, Contrast

ELEMENTS AND COMPOUNDS

Including, but not limited to:

• Element – a pure substance composed of a single type of particle (atom)

  • Type of particle – atom 

  • Organized on the periodic table of elements 

  • Represented by a chemical symbol

    • One or two letters representing an element

      • H – hydrogen

      • He – helium

      • Li – lithium

      • Be – beryllium

• Compounds – a pure substance composed of two or more different types of particles (atoms) of different elements that are joined together

  • Type of particle – molecule

  • Represented by a chemical formula

    • Each type of element in the compound is represented by its chemical symbol.

      • CO – carbon monoxide

      • NaCl – sodium chloride

    • The proportion (ratio) of each element in a compound is constant.

    • The number of atoms represented by specific ratios as determined by subscripts

      • CO2 – carbon dioxide

      • H2O – water

      • C6H12O6 – glucose