MODERN PHYSICS: V 6 Quarks 6 leptons (electron, 3 neutrinos, two others) Hadrons: Baryons (3 quarks) and Mesons (2) Plus their antiparticles Four Fundamental forces Strong Force (gluons) Weak force (weird particles) Electromagnetic force (photons) Gravity (gravitons) - They both have mass - They have opposite sign - If they meet, they self-annihilate and release energy n p+ e-
The Energy Levels of the Hydrogen Atom (The Well) In order for an electron to change from a lower energy state to a higher energy state, the incident photon must have the exact amount of energy equivalent to the difference in energy levels of the hydrogen atom. Ephoton = Ei – Ef For example: an electron transitioning from the ground state (n=1) to a higher energy level (n=2) requires a photon of 10.2eV. If the photon had only 10eV of energy or 10.5eV of energy, nothing would happen!
Quantization of the Energy Levels of the Hydrogen Atom Ephoton = Ei – Ef While an electron in a hydrogen atom transitions from n=1 to n=3 it needs a photon with exactly 12.09eV (13.60eV – 1.51eV) of energy, how will it return to the ground state? When transitioning back to the ground state, the electron can take one of 3 possible transitions: 3 – 1, or 3 – 2 followed by 2 – 1. Each jump would emit a photon with an amount of energy equal to the difference between the two energy levels.
The Energy Levels of the Hydrogen Atom Excited level n En 2 3 4 5 6 7 8 9 10 1 -13.6 10.2 12.09 12.75 13.06 13.22 13.32 13.39 13.43 13.46 -3.4 1.889 2.55 2.856 3.022 3.122 3.188 3.232 3.264 -1.51 0.661 0.967 1.133 1.234 1.299 1.343 1.375 -0.85 0.306 0.472 0.572 0.638 0.682 0.714 -0.54 0.166 0.266 0.332 0.376 0.408 -0.38 0.1 0.165 0.21 0.242 -0.28 eV 0.065 0.11 0.142 -0.21 0.045 0.077 -0.17 0.032 -0.14 En = (-13.6 eV)•Z2/n2
The Energy Levels of the Hydrogen Atom 2 3 4 5 6 7 8 9 10 1 1.6E-18 1.9E-18 2.0E-18 2.1E-18 2.2E-18 -5.4E-19 3.0E-19 4.1E-19 4.6E-19 4.8E-19 5.0E-19 5.1E-19 5.2E-19 -2.4E-19 1.1E-19 1.5E-19 2.0E-19 2.1E-19 2.2E-19 -1.4E-19 4.9E-20 7.6E-20 9.2E-20 -8.7E-20 2.7E-20 4.3E-20 5.3E-20 6.0E-20 6.5E-20 -6.0E-20 1.6E-20 2.6E-20 3.4E-20 3.9E-20 -4.4E-20 Joules 1.0E-20 1.8E-20 2.3E-20 -3.4E-20 7.1E-21 1.2E-20 -2.7E-20 5.1E-21 -2.2E-20 En = (-2.18 x 10-18 J)•Z2/n2
The Energy Levels of the Hydrogen Atom 2 3 4 5 6 7 8 9 10 1 2.5E+15 2.9E+15 3.1E+15 3.2E+15 3.3E+15 4.6E+14 6.9E+14 7.3E+14 7.6E+14 7.7E+14 7.8E+14 7.9E+14 1.6E+14 2.3E+14 2.7E+14 3.0E+14 3.1E+14 3.3E+14 7.4E+13 1.1E+14 1.4E+14 1.5E+14 1.7E+14 4.0E+13 6.5E+13 8.0E+13 9.1E+13 9.9E+13 2.4E+13 5.1E+13 5.9E+13 Frequency in Hz 1.6E+13 2.7E+13 3.4E+13 1.1E+13 1.9E+13 E = hf
The Energy Levels of the Hydrogen Atom 2 3 4 5 6 7 8 9 10 1 Light
Key Ideas The atom is defined as a probability cloud of electrons with a centrally located nucleus. The nucleus is fractionally smaller compared to the entire atom (1/100,000th). J.J. Thompson developed the first working model of the atom – the plum-pudding model. Earnest Rutherford developed the nuclear/planetary model of the atom as a result of the gold foil experiment. Neils Bohr further developed the planetary model of the atom and solved many questions about the hydrogen atom.
Covered Standards: Mon 5/7 5.3f Among other things, mass-energy and charge are conserved at all levels (from subnuclear to cosmic). 5.3g The Standard Model of Particle Physics has evolved from previous attempts to explain the nature of the atom and states that: • atomic particles are composed of subnuclear particles • the nucleus is a comglomeration of quarks which manifest themselves as protons and neutrons • each elementary particle has a corresponding antiparticle Stress Tues 5/8: 5.3b Charge is quantized on two levels. On the atomic level, charge is restricted to multiples of the elementary charge (charge on the electron or proton). On the subnuclear level, charge appears as fractional values of the elementary charge (quarks). 5.3j The fundamental source of all energy in the universe is the conversion of mass into energy.*
Covered Standards: Wed 5/9 5.3j The fundamental source of all energy in the universe is the conversion of mass into energy.* 5.3a States of matter and energy are restricted to discrete values (quantized). 5.3c On the atomic level, energy is emitted or absorbed in discrete packets called photons.* 5.3 Compare energy relationships within an atom’s nucleus to those outside the nucleus. i. interpret energy-level diagrams ii. correlate spectral lines with an energy-level diagram
observe and explain energy conversions in real-world situations recognize and describe conversions among different forms of energy in real or hypothetical devices such as a motor, a generator, a photocell, a battery 4.1b Energy may be converted among mechanical, electromagnetic, nuclear, and thermal forms.
4. 3a An oscillating system produces waves 4.3a An oscillating system produces waves. The nature of the system determines the type of wave produced. 4.3d Mechanical waves require a material medium through which to travel. 4.3g Electromagnetic radiation exhibits wave characteristics. Electromagnetic waves can propagate through a vacuum. 4.3l Diffraction occurs when waves pass by obstacles or through openings. The wavelength of the incident wave and the size of the obstacle or opening affect how the wave spreads out. 4.3 Explain variations in wavelength and frequency in terms of the source of the vibrations that produce them, e.g., molecules, electrons, and nuclear particles. iv. differentiate between transverse and longitudinal waves
5.3h Behaviors and characteristics of matter, from the microscopic to the cosmic levels, are manifestations of its atomic structure. The macroscopic characteristics of matter, such as electrical and optical properties, are the result of microscopic interactions. 5.3i The total of the fundamental interactions is responsible for the appearance and behavior of the objects in the universe.
5. 3d The energy of a photon is proportional to its frequency. 5 5.3d The energy of a photon is proportional to its frequency.* 5.3e On the atomic level, energy and matter exhibit the characteristics of both waves and particles.