The Periodic Table

* school science chemistry
[2025-11-26 Wed]

1. The periodic table displays the Elements

  • Dmitri Mendeleev organized the table in order of atomic mass and found patterns of repeating physical and chemical properties
  • Color represents its state at room temperature
    • RED=gas
    • Black=Solid
    • Blue=Liquid
    • White=Man made

2. Atomic Number

The atomic number is the number of protons in an atom's nucleus. It identifies the atom.

3. Mass Number

The mass number is the number of protons and neutrons in a nucleus.

3.1. Neutrons

The amount of neutrons in an atom is equal to the mass number - atomic number,

4. Vertical Columns are called Groups

  • 1: Alkaline metals. Shiny, soft, very reactive, low density
  • 2: Alkaline earth metals. Harder, and less reactive
  • 17: Halogens. Very reactive and poisonous
  • 18: Noble gases. Not reactive at all

5. Elsewhere

5.1. References

5.2. In my garden

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