UNIT 4 - ELECTRONS

I.          Energy and Electrons

A.         Ground state vs. excited state

B.         Transitions between ground state and excited state

1.          How energy is involved

3.          Photons - light as a wave

C.          Determining energy of an electron

1.          Planck

2.         Calculations - light as a particle<

D.         Spectroscopy

1.          Absorption and emission

2.          Bright line spectra

II.         Electron Arrangement

A.         Energy levels, sublevels, orbitals

B.         Electron configurations

C.          Noble Gas Configurations

D.         Highest Occupied Energy Level (HOEL)

E.         Valence Electrons

F.          Orbital notation

G.         Electron dot diagrams

H.         Exceptions to electron configuration rule (Honors only)

I.          Quantum numbers (Honors only)

North Carolina Essential Standards and Clarifying Objectives:

Chm. 1.1  Analyze the structure of atoms and ions.

1.1.2  Analyze an atom in terms of the location of electrons.

Analyze diagrams related to the Bohr model of the hydrogen atom in terms of allowed, discrete energy levels in the emission spectrum.

Describe the electron cloud of the atom in terms of a probability model.

Relate the electron configurations of atoms to the Bohr and electron cloud models.

1.1.3  Explain the emission of electromagnetic radiation in spectral form in terms of the Bohr model.

Understand that energy exists in discrete units called quanta.

Describe the concepts of excited and ground state of electrons in the atom:

1.  When an electron gains an amount of energy equivalent to the energy difference, it moves from its ground state to a higher energy level.

2.  When the electron moves to a lower energy level, it releases an amount of energy equal to the

energy difference in these levels as electromagnetic radiation (emissions spectrum).

Articulate that this electromagnetic radiation is given off as photons.

Understand the inverse relationship between wavelength and frequency, and the direct relationship between energy and frequency.

Use the “Bohr Model for Hydrogen Atom” and “Electromagnetic Spectrum” diagrams from the Reference Tables to relate color, frequency, and wavelength of the light emitted to the energy of the photon.

Explain that Niels Bohr produced a model of the hydrogen atom based on experimental observations. This model indicated that:

1.  an electron circles the nucleus only in fixed energy ranges called orbits;

2.  an electron can neither gain or lose energy inside this orbit, but could move up or down to another orbit;

3.  that the lowest energy orbit is closest to the nucleus.

Describe the wave/particle duality of electrons.

Chm. 1.3  Understand the physical and chemical properties of atoms based on their position on the Periodic Table.

1.3.2  Infer the physical properties of an element based on its position on the Periodic Table.

Write electron configurations, including noble gas abbreviations.  Included here are extended arrangements showing electrons in orbitals.

Identify an element based on its electron configuration.

Determine the number of valence electrons from electron configurations.