Chapter 7 The quantum mechanical atom.

1. Chapter 7The quantum mechanical atom.

2. Chapter 7 Chapter 8 Chapter 9 Chapter 11 Chapter 22

3. Chapter 7: The Quantum Mechanical Atom • Coverage: all sections • Overall Goals: • Elements are organized in the periodic table according to the arrangement of their electrons. This grouping also relates to their chemical and physical properties. With the information from this chapter, you will be able to: • describe the properties of electromagnetic radiation (or light) • apply these properties to study and elucidate the electronic structure of atoms (and molecules) • describe and justify the arrangement of electrons in a particular atom • predict the properties of an element according to its position in the periodic table

4. Chapter 7: The Quantum Mechanical Atom ELUCIDATING ELECTRONIC STRUCTURE Why we are looking into it Knowing the electronic structure of an atom OR a collection of atoms helps one to understand chemical reactions. Atoms are made up of a nucleus of positively charged protons and neutrons surrounded by a negatively charged cloud of electrons, atoms are electronically neutral. When atomscome together to form compounds their electron clouds are the first to interact. This interaction results in changes in theelectronic structure. Electrons determine many of an atoms chemical and physical properties. 4

5. Chapter 7: The Quantum Mechanical Atom ELUCIDATING ELECTRONIC STRUCTURE How electrons are behaving in atoms? Light is a tool that will help. Light = Electromagnetic radiations = Electromagnetic waves 7.1. Electromagnetic radiation provides the clue to the electronic structures of atoms

6. What is a wave? Some of you could have this in mind. 7.1. Electromagnetic radiation provides the clue to the electronic structures of atoms

7. Peak Waves are oscillations that move outwards from a disturbance and carry energy through space. Textbook Figure 7.2 Wavelength (λ, “lambda”) is the distance between identical points on successive waves. In other words, this is the distance between two peaks. The unit for wavelength is meter (m). Amplitude is related to the intensity of the wave. It is the vertical distance from the midline of a wave to the peak or trough. 7.1. Electromagnetic radiation provides the clue to the electronic structures of atoms

8. Nanometers (nm) Angstroms (Å) Micrometers (m) (1 m = 10-6 m) Millimeters (mm) (1 mm = 10-3 m) Centimetres (cm) (1 cm = 10-2 m) Meters (m) Units of Wavelength (1 nm = 10-9 m) (1 Å = 10-10 m) About 180 cm In nano scale please? 18 x 108 nm 7.1. Electromagnetic radiation provides the clue to the electronic structures of atoms

9. Textbook Figure 7.2 Frequency (ν, “nu”)isthe number of wave cycles in one second. The unit is the Hertz (Hz) Hz = s-1 7.1. Electromagnetic radiation provides the clue to the electronic structures of atoms

10. Frequency And Wavelength Are Related  =  = 7.1. Electromagnetic radiation provides the clue to the electronic structures of atoms

11. Frequency wavelength Frequency And Wavelength Are Related Inversely related 7.1. Electromagnetic radiation provides the clue to the electronic structures of atoms

12. Frequency And Wavelength Are Related Regardless of the frequency, light travels at the same speed, c: c=λ×ν The speed of light (c)= 2.99792458 × 108 m/s 3.00 × 108 m/s 7.1. Electromagnetic radiation provides the clue to the electronic structures of atoms

13. Calculation # 1. What is the wavelength (in nanometers) of the light having a frequency of 8.6 x 1013 Hz? Calculation # 2. What is the frequency of light having a wavelength of 456 nm? 7.1. Electromagnetic radiation provides the clue to the electronic structures of atoms

14. Light = Electromagnetic radiations = Electromagnetic waves Electromagnetic radiations come in a broad range of frequencies called the electromagnetic spectrum. Textbook Figure 7.3 7.1. Electromagnetic radiation provides the clue to the electronic structures of atoms

15. High frequencies, short wavelength Low frequencies, large wavelength 7.1. Electromagnetic radiation provides the clue to the electronic structures of atoms

16. Dark Side of the Moon - Pink Floyd. The visible part of the spectrum, called the visible light. It is composed of wavelength ranging from 400nm to 700 nm. Refraction of light through a prism gives a continuous spectrum. 7.1. Electromagnetic radiation provides the clue to the electronic structures of atoms

17. Some part of the spectrum have popular names: 7.1. Electromagnetic radiation provides the clue to the electronic structures of atoms

18. UV can cause sunburn, faster aging and cancer by directly interacting with the DNA of your cells.

19. X-rays and Gamma rays can cause cancer as well. Gamma rays are used to sterilize your food.

20. What is the energy of light? In 1900 Max Planck proposed that electromagnetic radiation can be viewed as a stream of tiny packets or quanta of energy called photons. Evidence for Particulate Behaviour of Light NRG is the link between Particulate and Wave Behaviour of Light http://www.ifae.es/xec/phot2.html h= Planck’s constant, 6.626 × 10-34 Js/photon 7.1. Electromagnetic radiation provides the clue to the electronic structures of atoms