3. Compounds are the combination of atoms with a specific ratio.
4.Chemical reactions involve reorganization of the atoms.
Thomson's atomic model
Raisin in the plum pudding
Experiment with cathode ray and conclude that matters consist of negatively charged particle called electron.
Calculate mass/charge ratio of electron = -5.686 * 10^12 kg/C
Rutherford's atomic model
Suggest the atomic nuclear model from the results of bombardment gold foil with alpha particles.
Atom consists of electrons which move around the positively charged center called nucleus.
atomic planetary model
Atom is mostly empty space. The size of nucleus is very small compare to the atom itself.
Quantum View of Atom
Bohr's model
Bohr proposed that atom has energy levels as circular orbits. Electrons move as wave in a specific energy levels. Electrons can transfer to different energy levels when they lose or gain energy.
Each energy level has specific quantum number (n) starts from 1,2,3...
Erwin Schrödinger used Quantum Mechanics to explain the energy state in the hydrogen atom.
The equation is called wave function. A specific wave function is often called an orbital.
Quantum number and atomic orbitals
the principal quantum number (n)
n = 1,2,3... small n, small size, close to nucleus, low energy
the orbital angular momentum quantum number (l)
give different shape of orbital
s p d f orbitals
the magnetic quantum number (ml)
give different orientation of orbital
the spin quantum number (ms)
represent spin of electron. Only two possible values : +1/2 and -1/2
Wave Particle Duality
In subatomic level, energy and matter cannot be distinguished. They have both light and particle properties.
light consists of particles called photon. Photon travels as wave.
Matter consists of atom and subatomic particles. Subatomic particles such as electrons travel or move as wave.