1 Materials Science Concepts MATS-535 Electronics and Photonics Materials Scope a – Atomic Structure and Atomic Number b – Bonding and Type of Solids Dr. Vladimir Gavrilenko Norfolk State University

2 Atomic Structure of Materials Basic building blocks of matter Classic vs. quantum treatments Models of atoms Bohr model

3 Bohr Atom

4 Shell Model. Carbon Atom

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6 Ionization Energy and Electron Affinity Ionization Energy – Smallest energy required to remove an electron from neutral atom Electron Affinity – Energy that is needed (or released) when one adds an electron to a neutral atom H Na H+H eV eV IE EA H-H- EA(H - )= eV required energy EA (Cl - )=-349. kJ/mol =-3.62 eV released energy 1 Takahashi et al Rev. Sci. Instr. 71, 1101 (2000) eV Cl 1 eV = 96.4 kJ/mol Cl -

7 Atomic Scale Units Fundamental au:

8 Atomic Mass and Mole Atomic mass: Avogadro’s number: One mole of a substance has a mass equal to its atomic (molecular) mass in grams

9 Atomic Bonding

10 Atomic Bonding Equilibrium conditions: Bond energy is an energy that is required to separate to particles Why the materials are stable? What prevents from the collapse?

11 Covalent Bonding

12 Methane Molecule

13 Diamond Crystal

14 Metallic Bond FCC Copper:

15 Ionic Bond

16 Simple Cubic Structure

17 Potential Energy Plot

18 Primary and Secondary Bonds Primary bonds: -Metallic -Ionic -Covalent Secondary bonds: -Van der Waals type -Hydrogen type

19 Van der Waals Bonds

20 Van der Waals Bonds

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