Physics Lecture Notes PDF
Document Details
Uploaded by TopQualityOboe
Tags
Summary
These lecture notes provide an introduction to atomic structure, including the Bohr model, isotopes, and the relationship between mass and energy, using formulas and real-world examples. The notes cover fundamental concepts in nuclear and atomic physics.
Full Transcript
PHYSICS Int oduction 1 Lec Int oduction Bohr Atom Model A more correct description of the atom states that we can’t know exactly where an electron is at any given time The position o...
PHYSICS Int oduction 1 Lec Int oduction Bohr Atom Model A more correct description of the atom states that we can’t know exactly where an electron is at any given time The position of an electron is described as a probability referred to as an electron cloud. Bohr Atom Model The atomic number Z of an element is equal to the number of protons in the nucleus of that element. The mass number A of an element is equal to the total number of nucleons (protons + neutrons). Isotopes of Elements Isotopes are atoms that have the same number of protons (Z1= Z2), but a different number of neutrons (N). (A1A2) different atomic masses and physical properties Example 2: The average atomic mass of Boron is 11.009305 u. What is the mass of the nucleus of one boron atom in kg? given that the atomic number of Boron is 5 (Mass of electron: 0.00055 u) Nucleus mass = atom mass - the mass of 5 electrons Mass of boron nucleus in u is = (11.009305 u) – (5 x 0.00055 u) = 11.00656 u Mass of boron nucleus in kg is = 11.00656 u * 1.6606 x 10-27 kg = 1.83 x 10-26 kg Einstein’s Equivalency Formula the relationship between the mass of a particle and its energy. What is the energy of 1 u? m= 1u E = (1u) x c2 = (1.66 x 10-27 kg)x(3 x 108 m/s)2 = 1.49 x 10-10 J E = 1.49 x 10-10 J = 931.5 M eV (megaelectron volt)