P-block

• Aluminum is used to make aircraft parts, beverage cans, and foil.
• P-block elements exhibit a wide range of chemical properties due to the varying number of valence electrons.
• Group 2A contains alkaline earth metals with two valence electrons that readily lose to form +2 ions.
• Tin is used to coat steel sheets to prevent rusting and form tinplate.
• Group 1A contains alkali metals with one valence electron that readily loses to form +1 ion.
• The periodic table can be divided into groups (columns) based on similarities in electron configuration and properties.
• These elements have valence electrons in the p orbital, which can hold a maximum of 6 electrons.
• The p-block elements are found on the right side of the periodic table and include groups 13 to 18.
• Boron has three valence electrons and forms compounds such as BCl3, BOCl2, and BF3.
• Lead is used as an alloying agent in brass and bronze.
• Na + Cl2 → ?

  2NaCl
• Mg + O2 → ?

  2MgO
• PbO + 2HCl → ?


  PbCl2 + H2O
• Al2O3 + 3H2SO4 → ?

  Al2(SO4)3 + 3H2O
• PbO + NaOH + H2O → ?

  NaPb(OH)3
• Al2O3 + 2NaOH + 3H2O → ?

  2NaAl(OH)4
• PbO2 + 4HCl → ?


  PbCl2 + 2H2O + Cl2
• SiCl4 + 2H2O → ?

  SiO2 + 4HCl
• Pb2+ + 2Cl- → ?

  PbCl2
• PbCl2 + 2Cl- → ?

  [PbCl4]2-
• Pb2+ + 2OH- → ?

  Pb(OH)2
• Pb(OH)2 + 2OH- → ?

  [Pb(OH)4]2-
• Pb2+ + 2I- → ?

  PbI2
• 1. block elements


  The six columns to the right hand side of the periodic table, starting from boron
• 1. block elements


  • Have the outermost electrons held in the p-orbital
  • Typically lose these electrons to form positively charged cations
  • Cations increase in stability down a group
• Amphoteric nature


  • Bonding of some p-block elements and their ions is partially ionic and covalent
  • Can react as both an acid and a base
  • React to form a salt and water in neutralisation reactions

  
• Amphoteric elements


  • Aluminium
  • Lead

  
• Inert pair effect


  • Increasing stability of the inert pair cations as you descend Groups 3, 4 and 5
  • Lower valencies become more stable as the group is descended
  • Inert pair of electrons in the outermost atomic s-orbital remain unshared in compounds

  
• Atoms with atomic number below 20 tend to combine so their valence shells each have 8 electrons (octet rule)
• There are exceptions to the octet rule: if molecules have an odd number of electrons, if molecules contain atoms which have more than 8 electrons, or if molecules contain atoms with less that 8 electrons
• Exceptions to the octet rule

  • Boron in BF3 with 6 electrons
  • Aluminium in AlCl3 with 6 electrons
  • Sulfur in SF6 with 12 electrons

  
• Aluminium hexachloride (Al2Cl6)


  • Donor-acceptor dimer
  • Two chlorine atoms share their lone pair of electrons with two aluminium atoms to form dative bonds

  
• Ammonia boron trifluoride (NH3.BF3)


  • Donor-acceptor dimer
  • Nitrogen atom donates its lone pair of electrons to the boron atom, forming a coordinate bond

  
• Boron nitride


  • Has the empirical formula BN
  • Can form very large compounds in giant cubic or hexagonal structures
  • Cubic form has a tetrahedral bond network similar to diamond
  • Hexagonal form has a layered structure similar to graphite

  
• Boron nitride


  • Very inert
  • Has a very high melting point
  • One of the hardest known materials after diamond
  • Hexagonal form is a good lubricant and can form nanotubes

  
• As you descend Group IV

  • Stability of the +4 oxidation state reduces
  • Stability of the +2 oxidation state increases
• Reaction between CO and copper oxide

  CO acts as the reducing agent

  
• Reaction between PbO2 and hydrochloric acid

  Pb(IV) acts as the oxidising agent

  
• PbO


  • Ionic compound with a relatively large amount of covalent character
  • Amphoteric, can act as both an acid and a base
• CO2


  • Has acidic properties
  • Equilibrium set up in water: CO2 + H2O ⇌ H+ + HCO3-
  • Simple covalent molecule with weaker forces of attraction
  • Polar molecule which is soluble in water