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CHEMISTRY - DACS 1232. Fakulti Kejuruteraan Mekanikal, UTeM. Lecturer: IMRAN SYAKIR BIN MOHAMAD MOHD HAIZAL BIN MOHD HUSIN NONA MERRY MERPATI MITAN. Electronic Structure of Atoms & Periodic Table. Chapter 4. Quantum Numbers. Principal quantum number – ( n ).
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CHEMISTRY - DACS 1232 Fakulti Kejuruteraan Mekanikal, UTeM Lecturer: IMRAN SYAKIR BIN MOHAMAD MOHD HAIZAL BIN MOHD HUSIN NONA MERRY MERPATI MITAN Electronic Structure of Atoms & Periodic Table Chapter 4
Quantum Numbers Principal quantum number – ( n ) Angular momentum quantum number – ( l) Magnetic quantum number – ( ml) Spin quantum number – ( ms)
n=1 n=2 n=3 Quantum Numbers (n, l, ml, ms) principal quantum numbern n= 1, 2, 3, 4, …. distance of e- from the nucleus
Quantum Numbers(n, l, ml, ms) angular momentum quantum numberl for a given value of n,l= 0, 1, 2, 3, … n-1 l = 0 s orbital l = 1 p orbital l = 2 d orbital l = 3 f orbital n = 1, l = 0 n = 2, l = 0 or 1 n = 3, l = 0, 1, or 2 Shape of the “volume” of space that the e- occupies
l= 0 (s orbitals) l= 1 (p orbitals)
Quantum Numbers (n, l, ml, ms) magnetic quantum numberml for a given value of lml= -l, …., 0, …. +l for l = 0 (s orbital)ml= 0 if l = 1 (p orbital),ml= -1, 0, or +1 if l = 2 (d orbital),ml= -2, -1, 0, +1, or +2 orientation of the orbital in space
ml = -1 ml = 0 ml = 1 ml = -2 ml = -1 ml = 0 ml = 1 ml = 2
Quantum Numbers (n, l, ml, ms) spin quantum numberms ms= +½or -½ ms = +½ ms = -½ Experimental arrangement for demo the spinning motion of electrons Q & A
Quantum Numbers (n, l, ml, ms) Existence (and energy) of electron in atom is described by its unique Quantum Numbers Pauli exclusion principle No two electrons in an atom can have the same four quantum numbers.
How many electrons can an orbital hold? Quantum Numbers (n, l, ml, ms) Shell – electrons with the same value of n Subshell – electrons with the same values of nandl Orbital – electrons with the same values of n, l, andml
How many electrons can be placed in the 3d subshell? How many 2p orbitals are there in an atom? Q & A
number of electrons in the orbital or subshell principal quantum number n angular momentum quantum number l 1s1 Electron configuration is how the electrons are distributed among the various atomic orbitals in an atom. 1s1 Orbital diagram H
Order of orbitals (filling) in multi-electron atom “Fill up” electrons in lowest energy orbitals (Aufbau principle) 1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p < 6s
C 6 electrons C 1s22s22p2 B 5 electrons B 1s22s22p1 Li 3 electrons Li 1s22s1 H 1 electron H 1s1
The most stable arrangement of electrons in subshells is the one with the greatest number of parallel spins (Hund’s rule). Ne 10 electrons Ne 1s22s22p6 F 9 electrons F 1s22s22p5 O 8 electrons O 1s22s22p4 N 7 electrons N 1s22s22p3
What is the electron configuration of Mg? What are the possible quantum numbers for the last (outermost) electron in Cl?
2p 2p Paramagnetic Diamagnetic unpaired electrons all electrons paired
Q & A session Name the orbital described by the following quantum numbers : • n = 3, l = 0 • n = 3, l = 1 • n = 3, l = 2 • n = 5, l = 0
Q & A session Give the n and l values for the following orbital a. 1s b. 3s c. 2p d. 4d e. 5f What and the possible ml values for the following types of orbital? a. s b. p c. d d. f
Q & A session How many possible orbital are there for n = a. 4 b. 10 How many electrons can inhabit all of the n = 4 orbital? Place the following orbital in order of increasing energy: 1s, 3s, 4s, 6s, 3d, 4f, 3p, 7s, 5d, 5p
Q & A session Write electron configurations for the following atoms: a. H b. Li+ c. N d. F- e. Ca
Q & A session Draw an orbital diagrams for atoms with the following electron configurations: 1s22s22p63s23p3
ns2np6 ns1 ns2np1 ns2np2 ns2np3 ns2np4 ns2np5 ns2 d10 d1 d5 4f 5f Ground State Electron Configurations of the Elements
Electron Configurations of Cations and Anions Of Representative Elements Na [Ne]3s1 Na+ [Ne] Atoms lose electrons so that cation has a noble-gas outer electron configuration. Ca [Ar]4s2 Ca2+ [Ar] Al [Ne]3s23p1 Al3+ [Ne] H 1s1 H- 1s2 or [He] Atoms gain electrons so that anion has a noble-gas outer electron configuration. F- 1s22s22p6 or [Ne] F 1s22s22p5 O2- 1s22s22p6 or [Ne] O 1s22s22p4 N3- 1s22s22p6 or [Ne] N 1s22s22p3
-1 -2 -3 +1 +2 +3 Cations and Anions Of Representative Elements
What neutral atom is isoelectronic with H- ? F-: 1s22s22p6 or [Ne] Na+: [Ne] Al3+: [Ne] O2-: 1s22s22p6 or [Ne] N3-: 1s22s22p6 or [Ne] Na+, Al3+, F-, O2-, and N3- are all isoelectronic with Ne
Electron Configurations of Cations of Transition Metals When a cation is formed from an atom of a transition metal, electrons are always removed first from the ns orbital and then from the (n – 1)d orbitals. Fe: [Ar]4s23d6 Mn: [Ar]4s23d5 Fe2+: [Ar]4s03d6 or [Ar]3d6 Mn2+: [Ar]4s03d5 or [Ar]3d5 Fe3+: [Ar]4s03d5 or [Ar]3d5