Periodic Table

Periodic Table

1. Mass Number: The sum of protons and neutrons of an element in nucleus of an atom.

2. Atomic Number: Sum of protons in nucleus of atom

3. Isotope: Atoms of same element that have different mass numbers as a result of different amounts of neutrons in nucleus of atom

4. Mass Spectrometer

   • Functions
     • Identify presence of isotopes
     • Measure rel abundances of isotopes
     • Identify compounds
   • Principle: Charged particles moving in a magnetic field are deflected to different extents based on their masses and are thus separated according to these masses
   • Steps
     • 1. Vaporisation
     • 2. Ionistaion
     • 3.Accelaration
     • 4.Deflected in mag field
     • 5. Detection

5. Relative Atomic Mass: The average of the mass numbers of isotopes of an element as they occur naturally, taking into account their abundances and expressed on a scale in which the atoms of Carbon-12 isotope have a mass of 12 units

6. Electron Configuration (Shows arrangement of electrons in atom)

   • S2,P6,D10
   • NOTE: Cr and Cu 3d filled before 4s
   • Eg. 1s2, 2s2,2p6,3s2,3p6,4s2,3d10.......
   • Aufbau Principle: When building up atom in it's ground state, the electron occupy lowest available energy levels
   • Hund's Rule of Maximum Multiplicity: When two or more orbitals of equal energy are available, the electron occupy them singly, then doubly
   • Pauli's Exclusion Principle:No more than two electrons can occupy an orbital and they must have opposite spin