Atomic Structure

Atomic Structure

1. Atomic + Mass Numbers

   • Atomic number shows:
     • No. of protons in nucleus
     • No of electrons in neutral atom
     • Position of element in periodic table.
   • Mass no: sum of number of protons and number of neutrons.
   • Particle
     • Electron
       • Relative mass: negligible
       • Relative charge: -1
     • Proton
       • Relative charge: +1
       • Relative mass: 1
     • Neutron
       • Relative mass: 1
       • Relative charge: 0
       • Mass no. - atomic no.

2. Isotopes

   • Atoms with same atomic number but different mass numbers.

3. Relative Mass

   • Relative Atomic Mass: Mean mass of atoms of an element relative to mass of 1/2 of mass of isotope carbon-12.
   • Relative Isotopic Mass: Mass of the atoms of an isotope relative to the mass of atoms of isotope carbon-12.
   • Carbon-12 is standard measurement of relative masses.
   • Relative molecular mass: add up relative atomic masses of all atoms present.
     • Relative formula mass: where compounds contain ions.