Trends in the periodic table

• How does atomic radius change down a group?

  It increases as you go down
• How does atomic radius change across a period?

  It decreases as you go left to right
• Why do atoms get bigger down a group?

  More shells are added to the atoms
• Why do atoms get smaller across a period?

  More protons increase attraction to electrons
• What is electronegativity?

  Attraction of an atom for shared electrons
• Which atom is the most electronegative?

  Fluorine
• Why is fluorine the most electronegative atom?

  It has more protons and is smaller
• Why don't noble gases have electronegativity values?

  They do not form bonds
• What happens if the difference in electronegativity is greater than two?

  One atom gains all the electrons
• Which group of metals has a higher melting point, group one or group two?

  Group two metals
• Why do group two metals have higher melting points than group one?

  They have more delocalized electrons
• How does melting point change down a group?

  It decreases as you go down
• Why does melting point decrease down a group?

  Bigger atoms reduce electrostatic attraction
• What are the trends in atomic radius, electronegativity, and melting point in the periodic table?

  • Atomic radius: Increases down a group, decreases across a period.
  • Electronegativity: Increases across a period, decreases down a group.
  • Melting point: Group two > Group one; decreases down a group.
• Why does beryllium have a higher melting point than lithium?

  Beryllium has more delocalized electrons
• Why does lithium have a higher melting point than sodium?

  Lithium is smaller than sodium
• Which element has the highest ionization energy among the first 20 elements?

  Helium
• Which element has the lowest ionization energy among the first 20 elements?

  Francium