Atomic orbital region of space in which there

• Atomic orbital: region of space in which there is a high probability of finding an electron. • A quantum of energy is the amount of energy required to move an electron from one energy level to another energy level • Energy level the specific energies an electron in an atom or other system can have. • Aufbau principal: • Electrons occupy the orbitals of lowest energy first. • Each box is a atomic orbital

• Hund’s Rule • Electrons occupy orbitals of the same energy • One electron in each orbital until all the orbitals contain one electron with the same spin • Second electrons then occupy each orbital so that their spins are paired with the first electron I the orbital. • Each orbital will eventually hold 2 electrons. • Electrons have opposite spins in the orbital

• Quantum mechanical model: The modern description of the electrons in atoms, the quantum mechanical model, comes from the mathematical solutions to the Schrodinger equation. • Ground state: electron has the lowest possible energy. • Excited state: when an electron in the outer energy level, absorbs energy

• Write the electron configuration(1 S 2, 2 S 2, …) and orbital diagram ( ) for: • Carbon • Argon • Nickel

Identify the element • 1 s 1, 2 s 2, 2 p 6, 3 s 1 • 1 s 2, 2 p 6, 3 s 2, 3 p 6, 4 s 2, 3 d 5

Can you use this table? How many orbital in 4 p? How many electrons in the s orbital? How many sublevels in the 3 rd principal energy level?

• Stable electron configurations are likely to contain filled energy sublevels. • Which element has 3 electrons in its 2 p sublevel? • Oxygen, argon, phosphorous • Which has the highest energy level completely filled? • Oxygen, argon, phosphorous • Which has the highest occupied energy level? • Oxygen, argon, phosphorous

• Why does the 5 s sublevel fill before the 4 d sublevel starts? • According to Aufbau principle, Electrons occupy the orbitals of lowest energy first. The 4 s is lower energy than the 3 d and the 5 s has lower energy than the 4 d. The lower the energy level the closer to the nucleus.

• Can the energy of a body change only small amounts? • Yes, this is always true. • Can the position and velocity of an electron in an atom be determined with great certainty? • No, we can find the probability of the location but not with great certainty • When electrons move to higher orbitals they absorb energy. When electrons move to lower orbitals they emit (give off) light.

• In Bohr’s model of the hydrogen atom, when the electron is in the ground state n=1 • The s level can contain 1 or 2 electrons. Inner or outer most still 1 or 2 • According to quantum ; mechanics, the motions of subatomic particles may be described as wavelike.