Chapter Seven Quantum Theory and the Electronic Structure of Atoms

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Orbital diagram Orbital Diagram: the electron configuration can also represented by the orbital diagram In the Orbital Diagram: Each box represents one orbital. Half-arrows represent the electrons. The direction of the arrow represents the spin of the electron.

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Orbital diagram Example: What is the electron configuration of Mg? Mg atom has 12 electrons (from: Periodic table (atomic number)) The Electron Configuration: 1s 2 2s 2 2p 6 3s = 12 electrons Orbital Diagram: 1s 2 2s 2 2p 6 3s 2 1s 3s 4s 5s 6s 7s 2p 3p 4p 5p 6p 7p 3d 4d 5d 6d 4f 5f 2s

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Atomic Orbitals What is the electron configuration of K? K atom has 19 electrons (from: Periodic table (atomic number)) The Electron Configuration: 1s 2 2s 2 2p 6 3s 2 3p 6 4s = 19 electrons Orbital Diagram: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 1s 3s 4s 5s 6s 7s 2p 3p 4p 5p 6p 7p 3d 4d 5d 6d 4f 5f 2s

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Atomic Orbitals What is the electron configuration of K +1 ? Atomic number19 Electron 19 -1= 18 K atom has 18 electrons (from: Periodic table (atomic number)) The Electron Configuration: 1s 2 2s 2 2p 6 3s 2 3p = 18 electrons Orbital Diagram: 1s 2 2s 2 2p 6 3s 2 3p 6 1s 3s 4s 5s 6s 7s 2p 3p 4p 5p 6p 7p 3d 4d 5d 6d 4f 5f 2s

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Short Notation Short Notation (abbreviation): means we write in the electron configuration of any element, the symbol of the Noble gas element in the previous period in brackets followed by the symbol of highest filled subshells in the outermost shells.

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Atomic Orbitals Example What are the possible quantum numbers for the last (outermost) electron in Cl? Cl atom has 17 electrons (from: Periodic table (atomic number)) The Electron Configuration: 1s 2 2s 2 2p 6 3s 2 3p = 17 electrons Orbital Diagram: 1s 2 2s 2 2p 6 3s 2 3p 5 Short notation: [Ne] 3s 2 3p 5

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms The Building-Up Principal Outermost subshell being filled with electrons

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Atomic Orbitals Example What is The electron configuration of 11 Na, 12 Mg, 16 S ? 11 Na 1s 2 2s 2 2p 6 3s 1 (OR) [Ne] 3s 1 12 Mg 1s 2 2s 2 2p 6 3s 2 (OR) [Ne] 3s 2 16 S 1s 2 2s 2 2p 6 3s 2 3p 4 (OR) [Ne] 3s 2 3p 4

Chapter Eight/ Periodic Relationships Among the Elements Development of the Periodic Table

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Atomic Orbitals Noble Gases: elements with electron configuration of complete s & p subshell (He, Ne, Ar, Kr, Xe, Rn), Group 8A

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Atomic Orbitals Representative Elements: elements with electron configuration of incompletely filled s or p subshell. Elements in Groups 1A-to-7A

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Atomic Orbitals Transition Elements: elements with electron configuration of incompletely filled d subshells or readily give rise to cations that have incompletely filled d subshells. Elements in Groups 1B-to-7B

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Exceptions The Stability of Half Filled & Filled d Orbitals 29 Cu:1s2 2s2 2p6 3s2 3p6 4s 2 3d 9 [Ar] 4s 2 3d 9 The stability of Filled d orbital → 29 Cu: [Ar] 4s 1 3d 10

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Atomic Orbitals 29 Cu: [Ar] 4s 1 3d Ag:[Kr] 5s 1 4d Mo: [Xe] 5s 1 4d 5 24 Cr: [Ar] 4s 1 3d 5

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Atomic Orbitals Paramagnetic substance: is the element that contain net unpaired electrons in the outermost subshell and is attracted by a magnet. e.g. Diamagnetic substance: is the element that do not contain net unpaired electrons (all electrons are paired) in the outermost subshell and is repelled by a magnet. e.g. Paramagnetic unpaired electrons 2p Diamagnetic all electrons paired 2p

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Atomic Orbitals Example 19 K Electronic configuration: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 Short notation: [Ar] 4s 1 Orbital diagram: 3s 2 3p 6 4s 1 Net one unpaired electron → Paramagnetic substance

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Atomic Orbitals Example 10 Ne Electronic configuration: 1s 2 2s 2 2p 6 Orbital diagram: 1s 2 2s 2 2p 6 All electrons are paired → Diamagnetic substance

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Atomic Orbitals P P D PPPP D

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Atomic Orbitals Example What are the valence electrons of vanadium (V)? 23 V: [Ar] 4s 2 3d 3 Example What are the valence electrons of Gallium (Ga)? 31 Ga: [Ar] 4s 2 3d 10 4p 1 The valence electrons are 4s 2 4p 1

Chapter Seven / Quantum Theory and the Electronic Structure of Atoms Periodic Classification of the Elements 21 ns 1 ns 2 ns 2 np 1 ns 2 np 2 ns 2 np 3 ns 2 np 4 ns 2 np 5 d1d1 d5d5 d 10 4f 5f Within a Period number of electrons increase Within a group (n) increase ns 2 np 6