5.111 Lecture Summary #8 Monday September 22, 2014
Readings for today: Section 1.14 – Electronic Structure and the Periodic Table, Section
1.15, 1.16, 1.17, 1.18, and 1.20 - The Periodicity of Atomic Properties. (Same sections in
5 and 4 ed.)
th th
Read for Lecture #9: Sections 2.1-2.3 – Ionic Bonds, Sections 2.14-2.16 - Covalent Bonds,
Section 2.5-2.6 – Lewis Structures (Same sections in 5 and 4 ed.)
th th
Topics: I. The Periodic table / Periodic trends
A. Ionization energy (IE) and Photoelectron spectroscopy
B. Electron affinity (EA)
I. THE PERIODIC TABLE / PERIODIC TRENDS
1869 Dmitri Mendeleev (Russian, 1834-1907) introduced a periodic table based on
reoccurring physical properties and chemical properties of the elements. Some
examples of grouping by properties:
• Li, Na, and K were originally grouped together in a column because they are all
soft, malleable, reactive metals.
• He, Ne, and Ar were grouped together because of their inertness.
Elements that are in the same column have related valence electron configurations:
• Li, Na, and K have _________ valence e in an s-state.
–
• He, Ne, and Ar have ______________ shells.
But column number does not determine all chemical/biological properties.
A. IONIZATION ENERGY (IE)
IE is the minimum energy required to remove an electron from an atom. IE refers to the
first IE unless otherwise specified.
IE = (binding energy) of the most weakly bound electron.
Ionization energy definitions:
B(1s22s22p1) B+ (1s22s2) + e– ∆E = IE = -E2p
IE º first IE: energy to remove an e– from the HOAO (highest occupied atomic orbital).
B+(1s22s2) + e– ∆E = IE2 = -E2s for B+
IE2 º second ionization energy. IE2 is always higher than the first IE.
B+2(1s22s1) + e– ∆E = IE3= -E2s for B+2
IE3 º third ionization energy.
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Readings for today: Section 1.14 – Electronic Structure and the Periodic Table, Section
1.15, 1.16, 1.17, 1.18, and 1.20 - The Periodicity of Atomic Properties. (Same sections in
5 and 4 ed.)
th th
Read for Lecture #9: Sections 2.1-2.3 – Ionic Bonds, Sections 2.14-2.16 - Covalent Bonds,
Section 2.5-2.6 – Lewis Structures (Same sections in 5 and 4 ed.)
th th
Topics: I. The Periodic table / Periodic trends
A. Ionization energy (IE) and Photoelectron spectroscopy
B. Electron affinity (EA)
I. THE PERIODIC TABLE / PERIODIC TRENDS
1869 Dmitri Mendeleev (Russian, 1834-1907) introduced a periodic table based on
reoccurring physical properties and chemical properties of the elements. Some
examples of grouping by properties:
• Li, Na, and K were originally grouped together in a column because they are all
soft, malleable, reactive metals.
• He, Ne, and Ar were grouped together because of their inertness.
Elements that are in the same column have related valence electron configurations:
• Li, Na, and K have _________ valence e in an s-state.
–
• He, Ne, and Ar have ______________ shells.
But column number does not determine all chemical/biological properties.
A. IONIZATION ENERGY (IE)
IE is the minimum energy required to remove an electron from an atom. IE refers to the
first IE unless otherwise specified.
IE = (binding energy) of the most weakly bound electron.
Ionization energy definitions:
B(1s22s22p1) B+ (1s22s2) + e– ∆E = IE = -E2p
IE º first IE: energy to remove an e– from the HOAO (highest occupied atomic orbital).
B+(1s22s2) + e– ∆E = IE2 = -E2s for B+
IE2 º second ionization energy. IE2 is always higher than the first IE.
B+2(1s22s1) + e– ∆E = IE3= -E2s for B+2
IE3 º third ionization energy.
1
