eps 102 C.1 geochem
Terms
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- who first used the term geochemistry?
- swiss chemist Schonbein in 1838
- science consists of two parts. what are they?
-
1) the knowledge it encompasses
2) the approach that achieves that knowledge - science consists of two quantities. what are they?
- observations and theories
- atomic number
- used to sort periodic table and is the number of protons in the nucleus
- mass of an atom
- proton number + neutron number, however an atom can have multiple neutron variations (isotopes)
- atomic weight
- depends on the masses of the various isotopes and their relative abundance
- what did Thompson do in 1918?
- demonstrated the existence of two Ne isotopes
- what are the four quantum numbers and what are they labeled?
-
principal, n
azimuthal, l
magnetic, m
spin, m_s - What does the principal, n, determine? What are typical values?
-
1,2,3...
determines electron's energy as well as mean distance from the nucleus - What does the azimuthal, l, determine? What are typical values?
-
0,1,2,3...n-1
determines the total angular momentum and the shape of the orbit - What does the magnetic, m, determine? Typical values?
-
-l...0...l
determines the z component of angular momentum and therefore the orientation of the orbit - What does the spin, m_s, determine? Typical values?
-
-1/2, 1/2
determines the electron's spin - The first three quantum numbers say what about the electrons surrounding the nucleus
- they are organized into shell, subshells, and orbitals
- What does the Pauli Exlusion Principle say?
- requires that no two electrons in an atom may have identical values of all four quantum numbers
- What is the first shell/period called? How many subshells? Quantum numbers?
-
K shell, one subshell (1s),
n=1, l=0, m=0.
2 elements: H and He - What is the second shell called? How many subshells?
-
shell: L
2 subshells: 2s(l=0), 2p(l=1) - How many orbitals does the p subshell have?
- 3(m=-1,0,1)
- How many electrons can the L shell accept?
- 8 (8 elements in period 2)
- What is the third shell called?
- M
- Why is the 3d subshell vacant in period 3?
- the possibility is therem but is energetically less favorable than electrons going in the subsequent shell.
- When do 3d subshells begin to fill?
- After the 4s orbital is filled
- Which orbitals correspond to the transition series metals, Sc through Zn?
- 5 3d orbitals
- Which orbitals correspond to the 2nd and third transition series metals?
- 4d and 5d orbitals
- The filling of the 4f shell correspond to which rare earth elements?
- Lanthanide
- The filling of the 5f shells correspond to which rare earth elements?
- Actinide
- How many electrons can each subshell level hold respectively: s,p,d,f
- 2,6,10,14
- What are the elements of group 1 called?
- alkalis--all have 1 electron in outermost s orbital
- What are the group 18 elements called?
- noble gasses--all have filled p subshell
- First Ionization Potential
- Energy required to remove the least tightly bound electron.
- Second Ionization Potential
- Energy required to move a 2nd electron, etc.
- electron affinity
-
energy given up in reactions:
ex. F + e- = F- - electronegativity
- differences in bond energy between an A-B molecule and the mean energies of A-A and B-B molecules. It quantifies the tendencty of an element to attract to a shared electron when bonded to another element
- In general, 1st ionization potential, electron affinity and electronegativities, ____from right to left, and to a less degree from top to bottom.
- decrease
- valency
- # of electrons that an element will either give up or accept
- valency of Uranium
- 6
- Ionic radius
- deduced from bond length when the atom is bonded to one or more other atoms.
- cation
-
postively charged atoms.
SMALL ionic radii - anions
-
negatively charged atoms.
LARGE ionic radius - _______ decreases as charge increases, due both to losee of electrons and shrinking of orbits of remaining electrons
- ionic radius
- electropositive
- ready to accept an electron, tend to form ionic bonds, rather than covalent bonds
- what are group 2 elements called?
- alkaline earths
- group 17 elements?
- halogens--highly electropositive
- elements of groups 13-16 tend to form what kind of bonds?
- covalent--tend to be less reactive and soluble
- what are the noble metals?
- Ru, Rh, Pd, Os, Ir, Pt--these elements tend to be very unreactive..dont oxidize like most other metals
- How do the rare earths metals vary?
- only by the number of electrons in the 4f shell