MOLE CONCEPT

• Atomic Mass (atomic weight)

  • mass of an atom expressed in atomic mass units (amu)
  • 1 amu = 1/12 mole carbon-12 atom
  • 12 amu standard in measuring of the elements
• Oganesson (Og)

  • heaviest man-made element in atomic weight
  • 118 protons
• Uranium - heaviest naturally occurring element
• Isotopes - atoms that have the same number of protons and electrons but with a different number of neutrons
• Relative Atomic Mass

  • average weight of all isotopes in a normal environment
  • standardized number and is assumed to be true for most of the planet Earth's crust
  • International Union of Pure and Applied Chemistry (IUPAC)
• Average atomic mass

  • natural percentage abundance is considered in calculating the weight of the naturally occurring isotopes of an element
  • two decimal places for final answer

  
• Amadeo Avagadro - Italian Scientist - provided the Avogadro's number
• Avogadro's Number, commonly denoted NA or L, is an SI defining constant with an exact value of 6.022×10²³ mol⁻¹.
• Units of Avogadro's:

  1. particles - general unit
  2. atoms - element
  3. formula units - ionic compound
  4. ions - ions (Na Cl)
  5. molecules - covalent compound (H2O, H2)
• Mole (mol) = NA = 6.022 x 10^23

  • amount of substance that contains as many elementary entities (atoms, particles, or molecules) as there are atoms in exactly 12 grams of carbon-12
• Molar Mass (M)

  • mass of substance per mole (g/mol)
  • molar mass = atomic mass (amu)
  • it's the quality in grams that equate the atomic mass of the element
• Molecular mass - sum of atomic masses of all elements in covalent compound
• Formula mass - sum of atomic masses of all elements in ionic compound
• When there's (●) symbol just plus it