General Chemistry

• Quantum Numbers - describes the designation of how electrons are distributed among various orbitals in principal shells and subshells.
• Shell - each division of space around the nucleus where electrons travel; also called the main energy levels (n).
• Orbital - a particular region in space around the nucleus where the probability of finding the electron is greatest.
• Principal Quantum Number, n - gives the main energy and the size of an orbital.
• Azimuthal Quantum Number, l - also called as the angular momentum number, defines the shape of the atomic orbital and comprises the sublevels  of the principal quantum number.
• Spin Quantum Number, ms - defines the orientation of the electron in an orbital.
• ELECTRON CONFIGURATION - gives the total number of electrons in a completely-filled main energy level given by the equation; 

  total electrons = 2n2
• expanded form - identifies all the electrons of the atom.
• abbreviated form - shows only the noble gas element that is isoelectronic with the configuration of the core electrons and the valence electrons.
• Aufbau (or building block) Principle -

  in filling orbitals with electrons, orbitals with the lowest energy is filled first.
• Hunds Rule of Maximum Multiplicity - in filling degenerate orbitals with electrons, each orbital is “half-filled” with one electron each before they are filled with any electrons in excess.
• Pauli’s Exclusion Principle - implies that no two electrons can have exactly the same set of quantum numbers.