Electron Orbitals Flashcards
2s orbital
1 node, higher energy, 2 electrons max.
3s orbital
2 nodes, 2 electrons max.
What is the electron configuration of Potassium (19)
1s(2)2s(2)2p(6)3s(2)3p(6)4s(1)
What is the order for filling electron orbitals?
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p
2p orbital
The lowest energy p orbital. 1 linear node = 2 alternate phase lobes. May be occupied by six electrons max, 2 in each of; 2px, 2py and 2pz.
3p orbital
1 linear and 1 circular node = 2 opposite lobes, each in 2 different phases. 6 electrons max
4p orbital
1 linear and 2 circular nodes. 6 electrons max
3d orbital
Lowest energy d orbital. 2 planar nodes = 5 d orbital shapes. 10 electrons max
The Principal Quantum Number (n)
Indicates the energy levels of an orbital (3s… n=3). Also indicates the number of nodes through n-1
Angular Momentum Quantum Number (l)
Describes the shape of the orbital and therefore angular distribution. May take any value between 0 and n-1. Eg. When n=3, l = 0 1 and 2
Magnetic Quantum Number (ml)
Describes the orientation of orbitals. Includes all values between -l and +l. E.g. n=3 so l=2 and ml = -2, -1, 0, 1, 2
Spin Quantum Number
Describes the spin of the electron. Ms = either +1/2 or -1/2
Pauli Exclusion Principal
No 2 electrons may be in the same quantum state
The Aufbau Principle
Electrons in atoms generally exist in their lowest possible energy state (ground state)
Hund’s Rule
Every orbital in a subshell will be occupied by one electron before any orbital in a subshell can be occupied by 2 electrons. All electrons in subshells organised singly will have the same spin.
Effective Nuclear Charge (Z eff)
The positive charge felt by an electron in a multi electron atom. The closer an electron is to the nucleus the closer Z eff will be to Z.
Outer electrons are partially shielded so Z eff is much lower than Z.
Nuclear Charge (Z)
Equal to the number of protons in a nucleus
(Trend) Across a period, Z eff ___?
Increases, as electrons are attracted more strongly to the nucleus.
(Trend) Down a group, Z eff ___?
Decreases as electron orbitals are further away from nucleus = greater shielding
(Trend) Anionic radii have a ____ Z eff than their neutral atoms
Smaller, as electrons have been gained = larger radii
(Trend) Cationic radii have a ____ Z eff than their neutral atoms
Larger, as electrons have been lost = smaller radii
Ionisation Energy (E i)
First I.E is the amount of energy required to completely remove an electron from an atom. Second I.E for the second etc.
(Trend) Ionisation energy _____ across a period
Increases, as electrons are attracted more strongly to the nucleus
(Trend) Ionisation energy _____ down a group
Decreases, as electrons are attracted less strongly to the nucleus
Electron Affinity (E ea)
The energy change when an electron is added to an atom in the gas phase. Energy is released = electron affinity (negative E i).
(Trends) Metals have a ____ E i
Low, as they readily lose electrons
(Trend) Non-metals have a ___ E i
High, as they readily gain electrons
Electronegativity
The ability of an atom to attract bonding electrons. Fluorine is the electronegative element
(Trend) Electronegativity _____ across a period
Increases
(Trend) Electronegativity _____ down a group
Decreases
1s Orbital
No nodes, low energy, 2 electrons max.
What is the p orbital bond order for diatomic molecules?
1s, 2sσ, 2sσ, 2pσ, 2pπ, 2pπ, 2pσ*
