Atomic orbitals, Electronic configuration and the periodic table Flashcards
The discrete lines observed in atomic spectra can be explained if?
Electrons like photons display the properties of both particles and waves.
Elections behave as… in an atom.
Standing stationary waves in an atom
What are standing stationary waves?
Waves that vibrate in time but do not move in space. There are different sizes and shapes of standing wave possible around the nucleus, known as orbitals.
Orbitals can hold a max of — electrons
2
Electrons in atoms have a fixed amount of energy called?
Quanta.
What does the principle quantum number (n) indicate? And what is it related to?
The main energy level for an electron. It’s related to the size of the orbital.
What does the angular momentum number (l) determine?
The shape of the subshell. - has values from 0 to n-1.
What does the magnetic quantum number (ml) determine?
The orientation of the orbital. - can have values between -L and +L
What does the spin magnetic quantum number (ms) determine?
The direction of spin. - can have balues of +1/2 or -1/2
What does heisenbergs uncertainty principle say?
“It is impossible to determine the exact position or momentum of an electron.”
What is the area where there is a high probability of finding an electron known as?
An orbital
What does Aufbau principle state?
Electrons fill orbitals in order of increasing energy.
What does hunds rule state?
When degenerate orbitals are available, electrons fill each singly keeping their spins parallel before pairing starts.
What does the Pauli exclusion principle state?
No 2 electrons in 1 atom can have the same set of 4 quantum numbers, therefore, no orbital can hold more than 2 electrons and these 2 electrons must have opposite spins.
In an isolated atom, the orbitals within each subshell are described as ——
Degenerate.
What can anomalies in trends of ionisation energies be explained by?
Considering the electron configurations
What can variation in first second and subsequent ionisation energies with increasing atomic number be explained in terms of?
The relative stability of different sub shell electron configurations.
What is there a special stability associated with?
Half filled and full sun shells.
The more stable the electronic configuration the…
higher the ionisation energy.
What is the definition of the first ionisation energy?
The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms.
The lower the ionisation energy, the…
Easier it is to remove an electron, the less stable the electron arrangement.
In general —— electrons are lost before —— electrons even though the —— subshell is filled before the —— subshell
4s, 3d, 4s, 3d
What is a dative covalent bond?
Formed when 1 atom provides both the electrons that form the bond.
What arrangement has:
Filled orbitals: 2
Bonding pairs: 2
Lone pairs: 0
Bond angle: 180°
Linear
What arrangement has:
Filled orbitals: 3
Bonding pairs: 3
Lone pairs: 0
Bond angle: 120°
Trigonal planar
What arrangement has:
Filled orbitals: 3
Bonding pairs: 2
Lone pairs: 1
Bond angle: 120°
Angular
What arrangement has:
Filled orbitals: 4
Bonding pairs: 4
Lone pairs: 0
Bond angle: 109.5°
Tetrahedral
What arrangement has:
Filled orbitals: 4
Bonding pairs: 3
Lone pairs: 1
Bond angle: 107.5°
Trigonal pyramidal
What arrangement has:
Filled orbitals: 3
Bonding pairs: 2
Lone pairs: 1
Bond angle: 104.5°
Angular
What arrangement has:
Filled orbitals: 5
Bonding pairs: 5
Lone pairs: 0
Bond angle: 120° & 90°
Trigonal bipyramidal
What arrangement has:
Filled orbitals: 5
Bonding pairs: 3
Lone pairs: 2
Bond angle: ?
T shaped
What arrangement has:
Filled orbitals: 6
Bonding pairs: 6
Lone pairs: 0
Bond angle: 90°
Octahedral
What arrangement has:
Filled orbitals: 6
Bonding pairs: 4
Lone pairs: 2
Bond angle: 90°
Square planar
Electron pair repulsion’s decrease in strength in the order:
Non-bonding pair/non-bonding pair > non-bonding pair/bonding pair > bonding pair/bonding pair
