Ch 8 Notes Flashcards
Electron Spin
4th Quantum Number
Electron spin magnetic quantum number
Magnetic behavior of electrons
Electrons behave as though they have a spin
Because of the spin the electron acts as a micro magnet creating a tiny magnetic field
Diamagnetic
Slightly repelled by a strong magnet
All of the electrons are paired
Paramagnetic
Attracted by a strong magnet
Paramagnetism arises from the spin of electrons
Spin can be thought of as quantized
Electrons are paired (and have opposite spins)
The spins of two electrons in an orbital do what to each other?
The paired spins cancel each other out
PARAMAGNETISM
The attraction of a substance to a magnet
Arises from the spin of electrons
Ions or elements must have at least 1 unpaired electron
Pauli Exclusion Principle
No two electrons in an atom can have the same four quantum numbers
Therefore no atomic orbital can contain more than two electrons
Orbital Box Diagrams
Represent electron configurations by placing arrows in boxes showing the direction of the spin
Aufbrau Principle
Electrons fill the shells from the lowest possible energy and up
Electrons fill shells so that the total energy of the atom is the lowest possible
For two subshells with the same value of “n+l” electrons do what?
Electrons are assigned first to the subshell of lower “n”
Effective Nuclear Charge
Z
The nuclear charge experienced by a single electron (in a multi-electron atom) which is effected by the presence of other atoms
The net positive charge attracting the electron is called the effective nuclear charge
Inner electrons can shield outer electrons from the charge of the nucleus
“Z” decreases with increasing “l”
Outer electrons are less tightly held to the atom
Degenerate
Orbitals in the same subshells with the same energy
Atomic Electron Configurations
spdf notation
orbital box notations
configurations - elements position on table - chemical properties
Noble Gas Notation
[He] 2s1
Elements in brackets are considered “core electrons”
What are valence electrons?
Electrons beyond the core
Hunds Rule
The most stable arrangement of electrons is with the maximum number of unpaired electrons all with the same spin
Fill orbitals with the same direction of spin first
What do the letter blocks tell?
They tell the orbital location for the outermost electron for that element
Transition elements fill what subshells?
The “d” subshells
How are cations formed?
By the removal of one or more valence electrons
Removal order p-(t)-s-d
pre-test-stress-disorder
Similar properties of elements are the result of what?
Similar valence electron configurations
Atomic Size
Distance between atoms in a sample of the element
Radius is 1/2 the distance between two nuclei
Periodic Trends of Atomic Size
Main Group Elements
Atomic radii increases going down a group (n is increasing)
Atomic radii decreases going down a period (core electrons stay the same)
Effective Nuclear Charge increases so atomic radius decreases
Size is determined by outermost electrons
Transition Metal Trends of Atomic Size
Filling of “d” orbitals effects the trend
Increase in E.N.C. is almost negated by the repulsion of electrons in the “d” orbitals
Radii decrease, level out, then slightly increase
What is Ionization Energy?
The energy required to remove an electron from the atom
POSITIVE because energy is required
Periodic Trends of Ionization Energies
Main Group Elements
Increase across - Increasing E.N.C
Decrease down - electron is increasingly farther away from the nucleus
Varies from “s” to “p” block and from half filled orbitals
Electron Affinity
the energy of a process in which an electron is acquired by the atom in the gas phase
Greater Affinity - More Negative EA
atoms that attract electrons to from negative ions
Electron Affinity and Ionization Energy and E.N.C
Generally a high ionization energy means a high electron affinity
Affinity increases across because of increasing effective nuclear charge
Affinity decreases down because electrons are generally farther away from the nucleus
Ion Sizes
Decreases as protons increase
E.N.C is the determining factor in size
Cations are smaller becuase the nucleus is acting on one less electron
Change in size is greatest when electron removed is last in a shell
Anions are larger becuase of increased electron repulsions
Isoelectronic Ions
Ions with the same number of electrons but with a different number of protons
