Quantum numbers and Periodic table II/

What is an orbital? It is the space around the nucleus in which the electron is found with a probability of 90%. The electron spends 90% of its time in that space. 90% II/

Different shapes of orbitals II/

2 1 3 Main shells sub- shells a b c d e f g a b g b g b g b g b g b g university 1 2 3 Main shells Faculty of art Faculty of engineering Faculty of science a b c d e f g sub- shells Arabic Engl. Mech civil chem phys Math a b g b g b g b g b g b g D M B M B M B M B M B M B Each student in the university is defined by a set of symbols: A Math student in the master program has the set: 3 g b II/

Similarly, electrons in atom are specified by a set of numbers, the quantum numbers: name symbol values Physical significance Principal Quantum Number n 1, 2, 3, 4, ……. Gives the main shell in which the electron exists. Determines largely the energy of the electron. Determines the size of the orbital. Azimuthal (secondary, angular moment) Quantum Number ℓ 0, 1, 2, …, (n-1) -Gives the subshell in which the electron exists. -contributes to energy of electron. -Determines the shape of the orbital Magnetic Quantum Number mℓ -ℓ, …, 0, … +ℓ -Determines the orientation of orbital in space Spin Quantum Number ms +/- 1/2 -orientation of rotation of electron around itself. II/

Main shell designation l-value orbital type s 1 p 2 d 3 f 4 g 5 h n-value Main shell designation 1 K 2 L 3 M 4 N 5 O II/

n mℓ 2n2 ℓ No. of orbitals No. of electrons (n-1) (-ℓ, …, +ℓ) 1 0 (s) 2 1 (p) -1, 0, 1 3 6 8 2 (d) -2, 1, 0, 1, 2 5 10 18 4 3 (f) -3, -2, 1, 0, 1, 2, 3 7 14 32 2n2 II/

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Nodes: Regions where electrons are not allowed to be present in Nodes: Regions where electrons are not allowed to be present in. Electron Probability of being there is zero. II/

3p 1 node II/ 3s: 3-0-1=2 nodes Number of nodes: n-ℓ-1 3d: 3-2-1=0 node II/