Periodicity

• What does the Periodic Table arrange elements by?

  Proton number
• What do all elements along a period have in common?

  Same number of electron shells
• What do all elements down a group have in common?

  Same number of outer electrons
• What is indicated by the group number in the Periodic Table?

  Number of outer electrons
• What are the groups classified as in the Periodic Table?

  s-block, p-block, d-block, f-block
• Which groups are included in the s-block?

  Groups 1 and 2
• What elements are classified in the p-block?

  Groups 3 to 0
• What are the transition metals classified as in the Periodic Table?

  d-block
• What are radioactive elements classified as in the Periodic Table?

  f-block
• What is periodicity the study of?

  Trends within the Periodic Table
• What happens to atomic radius along a period?

  It decreases
• Why does atomic radius decrease along a period?

  Increased nuclear charge with same electron shells
• What effect does increased nuclear charge have on outer electrons?

  Pulls them closer to the nucleus
• What happens to atomic radius down a group?

  It increases
• Why does atomic radius increase down a group?

  More electron shells are added
• What is electron shielding?

  Inner shells block attractive forces
• How does nuclear attraction change down a group?

  It is reduced
• What happens to ionisation energy along a period?

  It increases
• Why does ionisation energy increase along a period?

  Outer electrons are held more strongly
• What happens to ionisation energy down a group?

  It decreases
• Why does ionisation energy decrease down a group?

  Less energy is required to remove outer electron
• What is the relationship between melting points and bond strength in period three elements?

  Melting points are linked to bond strength

  
• What type of bonding do sodium, magnesium, and aluminium exhibit?

  Metallic bonding
• Why do melting points increase from sodium to aluminium?

  Greater positive charged ions and free electrons
• What type of structure does silicon have?

  Macromolecular structure
• Why does silicon have a very high melting point?

  Strong covalent bonds require much energy
• What type of molecules are phosphorus, sulphur, and chlorine?

  Simple covalent molecules
• What type of forces hold phosphorus, sulphur, and chlorine together?

  Weak van der Waals forces
• Why do phosphorus, sulphur, and chlorine have low melting points?

  Weak intermolecular forces require little energy
• What is the state of argon at room temperature?

  Gas
• Why does argon have a very low melting point?

  Weak van der Waals forces between individual atoms
• What makes argon very stable?

  Full outer shell of electrons
• What type of bonding does argon exhibit?

  Weak van der Waals forces
• What is the relationship between argon's atomic structure and its melting point?

  Stable structure leads to low melting point

  
• What are the physical properties of period 3 elements related to?

  • Bond strength
  • Structure of the elements

  
• How do the melting points of sodium, magnesium, and aluminium compare?

  • Sodium: low melting point
  • Magnesium: higher melting point
  • Aluminium: highest melting point
• How do the melting points of phosphorus, sulphur, and chlorine compare?

  • Similar low melting points
  • Simple covalent molecules
  • Weak van der Waals forces
• What are the melting points of period 3 elements based on their bonding types?

  • Metals: higher melting points (metallic bonding)
  • Silicon: very high melting point (macromolecular)
  • Nonmetals: lower melting points (simple covalent)

  
• What are the characteristics of noble gases like argon?

  • Exist as individual atoms
  • Full outer shell of electrons
  • Very stable with low melting points