trends

• Atomic radius


  As you go down a group, the atomic radius gets bigger. As you go left to right across a period, the atoms get smaller
• Atomic radius


  • More shells mean a bigger radius when going down a group. More protons lead to smaller atoms when going left to right across a period
• Electronegativity


  How much an atom in a compound attracts the electrons they share
• Electronegativity


  • Atoms become more attractive to electrons going from left to right across a period due to more protons. The smallest atom is the most attractive when going from top to bottom
• Noble gases don't form bonds, so electronegativity doesn't apply to them
• If the difference in electronegativity is greater than two, one atom will get all the electrons in an ionic bond
• Melting point


  Group two metals have a higher melting point than group one due to more delocalized electrons
• Melting point


  • Group two metals have more free electrons, leading to a higher melting point. Melting point decreases down a group as atoms get bigger
• As atoms get bigger down a group, the electrostatic attraction between nuclei and free electrons decreases, leading to a smaller melting point