sublevelsshapeeach principal energy level has its own number of sublevels (describes shape of orbitals) Sublevels - s sublevel: spherical (groups 1 and 2) - p sublevels: dumbbells (groups ) - d sublevels (transition metals) - f sublevels (lanthanides & actinides)
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Electron Configurations • Explains how electrons are distributed distributed among an atom’s orbitals • Each part identifies part of an electron’s “ address, address,” or location,within an atom • Example : 1s 2 is the electron configuration for helium - 1 1 is the highest energy level helium in which He places electrons electrons in the ground state - s s is the type type of orbital in which the electrons are being placed (called sublevels)
Transcript
Electron Configurations
• Explains how electrons are distributeddistributed among an atom’s orbitals
• Each part identifies part of an electron’s “address,address,” or location,within an atom
• Example: 1s2 is the electron configuration for helium- 11 is the highest energy level helium in which He
places electronselectrons in the ground state- ss is the typetype of orbital in which the electrons are being placed (called sublevels)- 22 is the numbernumber of electrons found in that orbital
Principal Energy Levels• 77 principal energy levels - one correlating to each
periodperiod (row) on the periodic table• Each level requires an increase increase in energy for
electrons to be placed there
• each principal energy level has its own number of sublevelssublevels (describes shapeshape of orbitals)
Sublevels
- s sublevel: spherical (groups 1 and 2)- p sublevels: dumbbells
(groups 13 - 18)- d sublevels
(transition metals)- f sublevels
(lanthanides & actinides)
Atomic Orbitals
Atomic Orbitals• Each sublevel
contains a different numbernumber of orbitals
• Orbitals are regionsregions where electrons are most likelylikely to be found in an atom
- ss sublevel has 11 orbital- pp sublevel has 33 orbitals - dd sublevel has 55 orbitals- ff sublevel has 77 orbitals
Atomic Orbitals
Each orbital holds only 2 electrons
Electron Configuration Rules
• Aufbau’s rule: electrons are placed in orbitals of lowest energy first- ground state: lowest energy level occupied by an
electron - excited state: any level above the ground state in
which an atom’s electron is found
• Hund’s rule: when electrons enter orbitals of equal energy, one electron enters each orbital until all the orbitals contain one electron with the same spin
• Pauli’s exclusion principle: each orbital can hold a maximum of two electrons with opposite spin
Sublevels & Periodic Table
Valence Electrons- elements in the same groupgroup react in a similar manner- they share similar reactions because they have the same number of valencevalence electrons- valence electrons are the electrons in the outermost outermost energy level
Atom/Ion
OrbitalDiagram
ElectronConfiguration
H
1 electron1s 1s1
1 UPE 1 VE
Atom/Ion
OrbitalDiagram
ElectronConfiguration
Be
4 electrons1s 1s22s22s
0 UPE 2 VE
Atom/Ion
OrbitalDiagram
ElectronConfiguration
B
5 electrons1s 1s22s22p12s 2p
1 UPE 3 VE’s
Atom/Ion
OrbitalDiagram
ElectronConfiguration
O
8 electrons1s 1s22s22p42s 2p
2 UPE’s 6 VE’s
Atom/Ion
OrbitalDiagram
ElectronConfiguration
Ne
10 electrons1s 1s22s22p62s 2p
0 UPE’s 8 VE’s
Atom/Ion
OrbitalDiagram
ElectronConfiguration
Mg
12 electrons1s 1s22s22p63s22s 2p 3s
0 UPE 2 VE
Atom/Ion
OrbitalDiagram
ElectronConfiguration
Cl
17 electrons
1s1s22s22p63s23p5
2s 2p 3s
1 UPE 7 VE
3p
• How many electrons can be placed into the 2p orbitals?
A. 6B. 2C. 4D. 8
• How many electrons can be placed in the third energy level?
A. 6B. 10C. 18D. 24
• How many sublevels are there in the fourth energy level?
A. 2B. 3C. 5D. 7
• How many electrons can be placed in the 4f sublevel?
A. 6B. 2C. 10D. 14
Noble Gas Shortcut• The Noble Gas shortcut can be used to represent
the electron configuration for atoms with many electrons. Noble gases have a full s and p and therefore can be used to represent the inner shell electrons of larger atoms.
• Lead:• Write the electron configuration for Xenon:
• Substitution can be used:• Manganese• Arsenic• Promethium
Ion Charges• Metals lose electrons (forming cations) in
order to have the same electron configuration as the nearest noble gas (very stable; typically 8 valence electrons
• Nonmetals gain electrons (forming anions) in order to have the same electron configuration as the nearest noble gas
