40 Cards in this Set
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Electron Spin
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moving charged particle generates a magnetic field
ms= +1/2 --- spins up and aligns with magnetic field
ms= -1/2 ---- spins down and aligns against the magnetic field
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Ferromagnetic
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occurs when the spins of unpaired electrons in a cluster of atoms in the solid align themselves in the same direction
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Paramagnetic
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In the absence of an external magnetic field, the unpaired electrons in the atoms or ions of a substance are randomly oriented. If a magnetic field is imposed, then these spins will tend to become aligned with the field.
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Diamagnetic
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Substances in which all electrons are paired (with two electrons of each pair having opposite spins) experience a slight repulsion when subjected to a magnetic field.
no unpaired electrons
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Pauli Exclusion Principle
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No two electrons in an atom can have the same set of four quantum numbers.
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Aufbau Principle
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Lowest electron levels must be filled first
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Hund's Rule
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When filling orbitals of the same Energy, electrons go into separate orbitals with parallel spins until all orbitals are 1/2 filled, then they pair up.
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Valence Electron Configuration
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When the D-orbital becomes filled, it is considered part of the core and not the valence configuration
2 exceptions- Cu24 - [Ar]4s1 3d5 , Cr29 - [Ar] 4s1 3d10
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Atomic Radius
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How Big?
As the number of electron increase, the atomic radius increases
fuzzy
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Atomic Size
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Metals are bigger than non-metals because of the loosely held valence electrons
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Effective Nuclear Charge
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Metals have low effective nuclear charges, while non-metals have high effective nuclear charges. This makes metals greater than non-metals in the same period.
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Ionization Energy
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The energy required to remove an electron from an atom in the gas phase.
endothermic
As the atomic radius decrease, the ionization energy increases
small atoms require more energy to ionize
as the atomic number increase, the ionization energy increases
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Electron Affinity
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The energy released when electrons are added to the gas phase atom
bumpy idea
little atoms have high electron affinities
exothermic
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Ion Sizes
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Cations halve in size
Anions double in size
In general, Anions are bigger than cations
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Lewis Structures
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Tell connectivity, not geometry
1. Draw skeletal structure
2. Count electron valence number
3. Single Bonds
4. Complete Octets on terminal atoms
5. Central atom octet? If yes, then done.
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Lewis Structure with Charge
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1. Molecular charge
2. Anions add charge, Cations subtract charge
3. Ion Notation -- [ ] with charge
4. Left over electrons put on central atom
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Incomplete Octets
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H, F, and terminal atoms -- Cl, Br, I cannot double/triple bond
not 4 pairs of electrons on the central atom
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Expanded Octet
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More than 4 pairs on electron on the central atom
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Free Radical
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1. Add extra electron to central atom
2. Never a complete Octet
3. Tend to be reactive
4. Paramagnetic
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Resonance Structures
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A way to represent multiple bonding in molecule or ion when more than one lewis structure can be written
1. Move double bonds not atoms
2. Equivalent Structures, same bonding pattern, same energy
3. Actual Molecule is the hybrid of all the structures
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Organic Molecules
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More than one center atom
All obey the octet rule
each has own geometry
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Linear
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180 degrees
2 terminal atoms
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Trigonal Planar
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120 degrees
3 terminal atoms
bent- 1 lone pair
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Tetrahedral
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109.5 degrees
4 terminal atoms
trigonal pyramidal- 1 lone pair
bent- 2 lone pairs
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Trigonal Bipyramidal
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90, 180, 120 degrees
5 terminal atoms
seesaw- 1 lone pair
t-shaped - 2 lone pairs
linear - 3 lone pairs
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Octahedral
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180, 90 degrees
6 terminal atoms
square pyramid- 1 lone pair
square planar- 2 lone pairs
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AXE notation
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A- atom
X - number of bonds
E - number of lone pair electrons
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number of orbitals
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n squared
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Atomic Radius
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As the atomic number increases, the atomic radius decreases
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Alkali Metals
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The alkali metals (group 1A) and the alkaline earth metals (group 2A), except Be, form basic solutions in water. They are very reactive metals and therefore are found in nature only combined with other elements.
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Noble Gases
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The noble gases (group8A) are the least reactive elements. They are all monatomic gases in elemental form.
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Isoelectronic
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Substances with the same number of electrons and the same electron configuration
In an isoelectronic series, the ion with the most protons is smallest because the nucleus exerts a stronger force of attraction and the electrons are pulled closer to the nucleus.
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AX4 E
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seesaw
180, 120, 90
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AX3E2
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t-shaped
90, 180
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AX2E3
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linear
180
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AX5
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trigonal bipyramid
90, 20, 180
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AX6
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octahedral
90, 180
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AX5E
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square pyramid
90, 180
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AX4E2
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square planar
90, 180
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Bond Order
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(sum of bonds between 2 atoms) / (# of equivalent structures)
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Chem 111: ION List