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Electrons in Atoms. Electron configuration. http://www.youtube.com/watch?v=Vb6kAxwSWgU. Electrons. The arrangement of electrons in an atom will determine the chemical and physical properties of that atom (or ion).
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Electrons in Atoms Electron configuration
Electrons • The arrangement of electrons in an atom will determine the chemical and physical properties of that atom (or ion). • Because of this it is important to know where those electrons are (or are most likely to be found)
Where do we find electrons? Electrons in atoms are arranged as LEVELS (n) SUBLEVELS (l) ORBITALS (ml) Think of these as the electrons address.
Energy Level (n) This tells you how far the electron is from the nucleus, the higher the energy level the further from the nucleus • Currently n can be 1 thru 7, because there are 7 periods on the periodic table
Energy Levels n = 1 n = 2 n = 3 n = 4
Sublevels • attempt to describe where the electrons are likely to be found • s, p, d, f ORBITALS • Found within the sublevels Each orbital can hold a maximum of 2 electrons
Types of Orbitals • The most probable area to find these electrons takes on a shape • So far, we have 4 shapes. They are named s, p, d, and f. • Each orbital has different “flavors” • s= 1 flavor • p = 3 flavors • d = 5 flavors • f = 7 flavors • Each “flavor” can hold a maximum of 2 electrons
How many electrons can be in a sublevel? Remember: A maximum of two electrons can be placed in an orbital. s orbitals p orbitals d orbitals f orbitals Number of orbitals 1 3 5 7 Number of electrons 2 6 10 14
Electron possible per energy level 2n2 = the number of electrons possible in an energy level • Ex: 3rd energy level, n=3 2(3)2 = 18
Electron Configurations 2p4 Number of electrons in the sublevel Energy Level Sublevel 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14…etc.
General Rules • Pauli Exclusion Principle • Each orbital can hold TWO electrons with opposite spins.
General Rules • Aufbau Principle • Electrons fill the lowest energy orbitals first. • “Lazy Tenant Rule”
General Rules • Hund’s Rule • Within a sublevel, place one e- per orbital before pairing them. • “Empty Bus Seat Rule” RIGHT WRONG
2s 2p 1s Notation • Orbital Diagram O 8e- • Electron Configuration 1s2 2s22p4
Core Electrons Valence Electrons Notation • Longhand Configuration S 16e- 2p6 2s2 1s2 3s2 3p4
Noble Gas Valence Electrons Notation • Shorthand Configuration S 16e- [Ne] 3s2 3p4
Lithium Group 1A Atomic number = 3 1s22s1 ---> 3 total electrons
Carbon Group 4A Atomic number = 6 1s2 2s2 2p2 ---> 6 total electrons