Periodicity

• The periodic table arranges elements by their proton number as well as their properties.
• The periodic table is arranged into periods (rows) and groups (columns).
• All the elements within a period will all have the same number of electron shells.
• All the elements within a group have the same number of electrons in their outer shell.
• The periodic table can be split into and s block, d block, p block and f block. Doing this allows you to identify which sub-shell all the electron go into.
• The atomic radius decreases across a period.

  As the number of protons increases, the positive charge of the nucleus increases which means that electrons are puled closer to the nucleus, making the atomic radius smaller.
• Melting points are linked to bond strength and structure.

  Melting points vary across a period as they depend on the structure of elements and the bonding within them.