Element Geochemistry Flashcards
Electronic structure
Determines the size, charge, and bonding character of an atom and/or ion. Which all changes the behaviour of an element
What are the 4 types of orbitals?
s, p, d, f
How many electrons can an S-type orbital hold?
2
How many electrons can a P-type orbital hold?
6
How many electrons can a D-type orbital hold?
10
How many electrons can a F-type hold?
14
The Aufbau Principle
Electrons are put into orbitals in order of increasing subshell energy
Higher shells does NOT = higher energy
Pauli Exclusion Principle
Each orbital can accommodate a max of 2 electrons and they must spin in opposite directions.
No two electrons have the same state at the same time.
Hund’s Rule
For a given subshell, one electron goes into each orbital before two electrons can be placed in any of them.
Enhanced Stability
Atoms achieve a state of enhanced stability when the available orbitals are either fully filled, half-filled, or empty
Electron Microprobe Analyzer (EMPA)
Tool that analyzes the chemical composition of rocks by x-rays (electron beam)
Four factors controlling behaviour of elements
1) Mass
2) Size
3) Charge (valence)
4) Bonding character
Is size proportional to mass?
No
Is the size of an atom = size of an ion?
No
True or False: Size of cation > Size of atom
False. Cation < Atom
True or False: Size of anion > Size of atom
True
True or False: The larger the + charge, the smaller the cation
True
True or False: The larger the - charge, the larger the anion
True
Why is the size of an ion important for element behaviour in crystals?
It determines whether certain elements can be accommodated by certain minerals
Electron donors
Give away electrons in order to achieve stability
Electron acceptors
Gain electrons in order to achieve stability
Cations
Positively charged, formed from atoms giving away electrons
Anions
Negatively charged, formed from atoms gaining electrons
What are 3 parameters affecting if an element tends to lose or gain electrons?
First ionization potential
Metallic character
Electronegativity
First Ionization Potential
The amount of energy needed to drive off an electron from the atom in the gaseous state
Metallic Character
A qualitative description of the extent that an element tends to give away electrons
Electronegativity
A measure of the ability of an atom in a molecule to attract electrons to itself
Ionic bond
Cations and anions are attracted to each other and form a bond
Covalent bond
When two elements having similar electron donor/acceptor character interact
True or False: Electron transfer is never 100% complete (no bond is 100%)
True
Ionic character
A measure of the extent an atom tends to form an ionic bond with another atom
Covalent character
A measure of the extent an atom tends to form a covalent bond with another atom
True or False: Elements from opposite ends of the periodic table tend to form ionic bond
True
True or False: Elements close to each other in the periodic table tend to form covalent bond
True
Goldschmidt’s classification of elements (4 groups)
Lithophile - silicates
Siderophile - iron
Chalcophile - sulfides
Atmophile - atmosphere
Why are noble gas elements enriched in the atmosphere rather than in the rocks?
Noble gases have a charge of 0. Rocks need bonds and noble gases don’t have them.
Why are certain elements always associated with each other?
They have similar electron structures
