The Periodic Table of Elements

• Physically, group 1 elements are soft, low in density, low in melting and boiling points, and shiny on the surface.
• Physically, going down group 17, elements darken in colour, and at room temperature changes from gas to liquid to solid.
• Group 18 - noble gases.

  Group 17 - halogens.

  Group 1 - alkali metals.
• Going down group 1 & 17, the atomic radius both increases, while the reactivity increases and decreases respectively. Group 1 atoms donate its valence electron easier, while group 17 attracts new electron harder.