Fundamental Ideas in Chemistry - C1

Atoms and elements are the building blocks of chemistry
when elements react they produce COMPOUNDS
ELEMENTS
1. *all substances are made of ATOMS
  1. atoms of each element are represented by a chemical symbol
    1. e.g. OXYGEN = O, SODIUM = Na
    2. atoms have a small central nucleus
      1. made of PROTONS and NEUTORNS surrounded by ELECTRONS
        Atoms contain PROTONS, NEUTRONS and ELECTRONS
        the relative electrical charges:
        the no. of ELECTRONS in an atom is EQUAL TO THE NO. OF PROTONS in the NUCLEUS
        atoms have no overall charge
2. *a substance made of only one sort of atom is called an ELEMENT
3. there are over 100 different elements
THE PERIODIC TABLE
1. ELEMENTS are shown on The Periodic Table
  1. The groups contain elements with similar properties
ATOMIC NUMBER and MASS NUMBER
1. all atoms of a particular element have the same number of protons
2. atoms of different elements have different numbers of protons
3. the NO. of PROTONS = ATOMIC NUMBER (PROTON NUMBER)
4. the total no. of PROTONS and NEUTRONS = MASS NUMBER
  1. (add together)
SHELLS AND ENERGY LEVELS
1. ELECTRONS occupy particular energy levels
2. each electron in an atom is at a particular energy level (in a particular shell)
3. the electrons in an atom occupy the lowest available energy levels (innermost available shells)
4. SHELLS fill in an order of 2, 8, 8,.....
5. ELECTRON STRUCTURE
  1. *the noble gases are unreactive because their outer shells are full

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	Creado por Georgia Freeman hace más de 12 años