11/11/08

Post date: Nov 10, 2008 9:48:30 PM

Bell Activity: What is an atom?

Building blocks

• • Atom - the smallest unit of an element that still behaves like that element

    • made of protons, neutrons, and electrons

      • protons and neutrons at the center, make up the nucleus

      • electrons orbit around the nucleus

    • Periodic Table

      • Atomic number is number of protons

      • Atomic mass is protons + neutrons

      • Same number of electrons as protons

      • Draw the atoms of Magnesium, Iron, Aluminum, and Zinc to turn in during class.

  • Molecule - two or more atoms that are bonded together

Matter is classified as either an element, a compound, or a mixture

• • Elements - made of only one kind of atom

    • • The types of building blocks we have

      • Marshmallows - different colors are different elements

      • The periodic table arranges elements by the properties of their atoms

        • • Number represents number of protons

          • Mass is protons and neutrons, electrons have VERY little mass

          • As a class, we create a visual table of elements (drawing each atom)

      • Examples - Copper wire made of only copper atoms, aluminum foil made of only aluminum atoms

      • Social example - men or women

  • Compounds - made of two or more types of atoms

    • • Marshmallows - multiple colors bonded together

      • Examples - water is hydrogen and oxygen, table salt is sodium and chlorine, sugar is hydrogen, oxygen, and carbon

      • We use chemical formulas to represent formulas

        • • Use element symbol from periodic table

          • Use numbers to note how many of each atom we have bonded together

      • Social example - a couple

  • Mixtures - Elements and/or compounds are mixed together, but could be separated again

    • • Marshmallows - multiple colors NOT bonded, or multiple different bonded molecules

      • Elements and compounds are pure substances, meaning their is a fixed ratio of components. Mixtures are not pure substances, meaning you could have any ratio of components in the mixture.

      • Compounds have 2 or more elements bonded together, and cannot be separated

      • The parts of mixtures are not bonded together, and can be separated

      • Can be solid in solid, liquid in liquid, gas in gas, or combinations.

      • Social example - non-couples in a room together, or couples in a room with other couples or with single people

• In groups of 3-4, create another analogy for elements, compounds, and mixtures to share with the class