Chemistry Lecture Notes

Electron Configurations

Japanese company makes beer with hydrogen in it

A truly weird development-beer with free hydrogen in it-is the topic of an Associated Press dispatch datelined Tokyo.

Asaka Beer Corp., according to the AP, makes this novel beverage by replacing part of the carbon dioxide in beer with hydrogen. The company's marketing director, Hideko Saito, is reported as saying that the carbon dioxide-hydrogen balance is maintained so as to prevent “the rate of combustion from increasing dramatically.” The bottle caps have safety valves to forestall excessive buildup of pressure with rising temperature. Also, the AP says, “the bottles are packed in special crates lined with concrete to prevent chain explosions in the event of fire.”

Why would anyone want beer full of hydrogen? Well, in Japan they have these karaoke sing-along bars and discotheques, which are very popular among 20-somethings. People whose lungs are spiked with hydrogen speak and/or sing in uncharacteristically high voices owing to the physical properties of the gas. As a result, the AP reports, “chic urbanites can now sing soprano parts on karaoke sing-along machines after consuming a big gulp of the [Hydrogen Beer].”

An offshoot of the Hydrogen Beer craze, says the AP, is blowing flames from one's mouth using a cigarette as an ignition source. “Many new karaoke videos feature singers shooting blue flames in slow motion, while flame contests took place in pubs everywhere in Tokyo on New Year's Eve.”

When the AP story was written, a bottle of Hydrogen Beer cost about 1,200 yen, or $11 in U.S. money. That ratio is no longer correct, however, because the value of the dollar has been tumbling. In any event, the AP says, Asaka has hesitated to market the beer in this country “due to legal complications.”

N

S S

two spin states

ms = + ½, –½

Spin quantum number, ms

spinning charge magnetic moment

Pauli exclusion principle

No two electrons in an atom can have all four quantum numbers the same.

n, l, and ml are characteristic of a given orbitalms can be + ½ or –½

two electrons can reside in an orbital when their spins are opposite (paired).

Electron configurations (ground state)

1. Fill orbitals with up to two electrons per orbital (opposite spins),starting with the 1s orbital and filling orbitals in increasing energy,until all electrons in an atom have been placed in orbitals.

2. Hund’s rule: when orbitals are the same energy (as within asubshell), fill the orbitals with one electron per orbital first, all thesame spin, then start pairing up.

H 1s1

1s

main shell, n

number of electrons in subshell

subshell, l

orbitalnotation

spectroscopicnotation

He 1s2 first shell filled stable configuration 1s (noble gas)

C ___ ___ ___ ___ ___

1s 2s 2p

O ___ ___ ___ ___ ___

1s 2s 2p

Ne ___ ___ ___ ___ ___

1s 2s 2p

Na

P

K

Sc

Reading electron configurations from the table

V Ru

Ni Sb

Zn Os

Ge Pb

Transition metals:

“rob” one electron from an s orbital to fill or half-fill a d orbital

Cr [Ar]4s23d4 [Ar]4s13d5

Mo

Cu [Ar]4s23d9 [Ar]4s13d10

Ag

Inner transition metals: forget it!

Classification of the elements

1. periods (rows): chemical properties vary in a periodic fashion groups (columns): elements in a group have similar properties

2. main group (representative) elements: groups 1A - 8A transition elements: groups 1B - 8B inner transition elements: lanthanides (rare earth elements), actinides

3. metals: lustrous, malleable, ductile, electrically conductive nonmetals: not lustrous, malleable, ductile, nor electrically conductive metalloids (semimetals, semiconductors): in between

4. named groupsgroup 1A: alkali metals (form alkaline solutions in water)group 2A: alkaline earth metals (")group 6A: chalcogens (copper-forming) [not often used]group 7A: halogens (salt-forming)group 8A: noble gases (inert gases; unreactive)