chapter 4 chemical bonding

• chemical bonding


  atoms of the same type or different type chemically joined together
• stable electronic configuration of noble gas

  atoms bond together to fill in all the gaps of the valence electrons to form noble gas
• types of bonding

  • ionic bonding
  • covalent bonding
• ionic bonding 


  involves the transfer of electrons from one atom to another atom
• ionic bonding occurs ...

  ionic bonding occurs between metal and non-metals
• ionic bonding (metals)


  metals loses electron to form positive ions (or cations)
• ionic bonding (non-metal)


  non-metals gain electrons to form negative ions (or anions)
• ionic bonding (metal non-metal)

  oppositely charged ions exert mutual electrostatic attractive forces between them that hold them together
• electrostatic attractive forces


  very strong force that holds ions oppositely charged tighter together in a compound are called ionic bonding
• ionic compound 


  ionic compound is electrically neutral because they have no net charge (negative and positive charge are same / equal)
• ions


  charged particle as the number of the proton is not longer equal to the number of electron
• formation of ion


  ion forms when atom loses or gains electrons
• postive charged ion


  • cation(loses electron)
  • usually a metal
  • more proton than electron
• negative charged ion


  • anion (gains electrons)
  • usually non-metal
  • fewer proton than electron
• covalent bonding


  atom share electrons to attain noble gas electronic configuration
• common anions

  
• ionic bond diagram

  dot and cross
• valency 


  refers to the number of electrons that must be gain or lost or shared in order for atom to attain noble gas electronic configuration
• covalent bond - chlorine 


  two chlorine atom come together and share 1 electron each so from 2,8,7 to 2,8,8 after sharing (called bonding pair , single covalent bond)
• covalent bond - chlorine

  • since electron shell of atom overlaps in covalent bond , the bond is hard to break
  • when chlorine atom bond they form a molecule
• covalent bond number (pairs)

  • single bond - 1 pair
  • double bind - 2 pairs
  • triple bond - 3 pairs
• covalent molecules

  • mostly simple molecules
  • simple molecules have countable number of atom in fixed ratio
• covalent drawing diagram

  dot cross diagram