Atomic Structure and Bonding Flashcards
The general form of the time-independent Schrodinger equation is given by:
HΨ =EΨ
Equation that describes the discreet energy levels in the hydrogen case:
E_(n )= R_(H ) (1/n^2 )
What do this two symbols mean?
H
Ψ
H - mathematical operator used to describe both the potential and kinetic energy of an electron
Ψ - wave function that describes the wave nature of an electron
Ψ^2 is proportional to …
… the probability of finding an electron with a given set of quantum numbers
… probability density function
Quantum number n (meaning and characteristic)
- principal quantum number
- describes the overall size
Quantum number l
- orbital angular momentum quantum number
- shape of the orbital
- ranging from 0 to (n-1)
Quantum number ml
- magnetic quantum number
- ranging from -l to l
Quantum number ms
- electron spin quantum number
- -1/2 or +1/2
Every orbital in a sub-shell receives one electron before double occupation occurs
Hund’s Rule of maximum multiplicity
What is the ionization energy?
It’s how much energy it takes to strip an electron from an atom
What happens to the ionization energy when the size of the atom increases?
It decreases.
What happens to the ionization energy when the size of the atom decreases?
It increases.
There are three primary bonds:
Ionic, Metallic and Covalent
The ionic bonds occurs between:
An electropositive element and a electronegative element. Between a metal and a non-metal
In which bond there is transfer of electrons from one atom to another
Ionic Bond
The force of an ionic bond can be calculated by ….. Law:
Coulomb’s Law
The covalent bonds occurs between:
An electronegative element and a electronegative element (or with itself)
In which bond there is sharing of electrons
Covalent Bond
Relative to the spin of the electrons, in covalent bonds they have to go through:
Spin Paring
Relative to direction, covalent bonds are …
significant anisotropy which means, they are directionally dependent
What’s the definition for electropositive:
Likely to give an electron
What’s the definition for electronegative:
Likely to receive an electron
Which bond leads to isotropic behaviour:
Ionic Bond
Why are ionic bonds stable?
Because the charge-charge interaction leads to stable bonds which results in high melting temperatures and good chemical stability.
Between hybrid orbitals there is a new bond formed called:
sigma bond
What’s one characteristic of sigma bonds:
Rotational freedom
What does hybridization means:
It’s the superposition of wave functions.
Concept of mixing atomic orbitals into new hybrid orbitals
In a double bond, a … is formed:
π Bond
How are sigma bonds formed?
They form between two covalently bonded atoms.
Are π bonds stronger or weaker compared to sigma bonds? Why?
Weaker, because there is significantly less orbital overlap
How are π bonds formed?
Between p orbitals that have the same direction.
Do π bonds have rotational freedom?
No
The metallic bond occurs between:
Electropositive elements
What is the main characteristic of a metallic bond?
Simple lattice of protons and a “sea” of electrons
Is there directionality in metallic bonds:
No
Secondary Bond are also known as
Van der Waals forces
Ideal Gas Law:
PV = N k_B T
Describe polarizability
Ability to form instantaneous dipoles, determines the dynamical response of a bound system to external fields
Keesom Forces form between …
… permanent dipoles
Two permanent dipoles that interact with each other have the ability to …
… promote the local alignment of the molecule
Debye Forces form between …
a molecule with a permanent dipole and a molecule with no dipole
The type of secondary bond that is always present is
London Dispersion Forces
Dispersion Forces form between …
Instantaneous Dipole (Spontaneous dipole) - Instantaneous Dipole (Induced Dipoles)
In secondary bonds, pull of certain atoms can bias …
the spatial location of e- cloud
Hydrogen Bonds form between:
H bonded to N, O or F and N, O or F
Which is the strongest secondary bond?
Hydrogen Bond: 5-10 KT
VdW: ~ 1KT
