CHEMISTRY FULL EXAM REVIEW

Ernest Rutherford- Gold Foil Experiment/Model

• Atom is mostly empty space.

• Positive charge is concentrated in a small, dense nucleus.

• Strong nuclear force holds the nucleus together.

Bohr’s improved model- summary

• Electrons move in fixed energy levels (orbits).

• Electrons do not lose energy while in an orbit.

• Electrons gain/lose energy by jumping between levels.

Quantum Mechanical Model of the Atom

The atom consists of a nucleus having a concentrated positive charge. There

is a very high probability of finding pulsating electron waves in regions of

space around the nucleus called orbitals. These regions are not sharply defined

like the orbits of Bohr's theory, but are somewhat "fuzzy"

Electron Configuration

the distribution of electrons in an atom’s atomic orbitals,arranged in shells and subshells (s,p,d,f) in order INCREASING ENERGY

AUFBAU PRINCIPLE

imaginary process of electron addition which ensures that the electrons enter oribtals in the following order

HUND’S RULE

No electron pairing takes place in p,d, or f orbitals until each of the given set contains 1 electron

PAULI EXCLUSION PRINCIPLE

No orbital can contain more than 2 electrons, and must have opposite spin numbers