A. Major Points and Concepts
* Review
* electrons orbit small positive core
* core is made up of protons and neutrons
* most of atom is empty space
* sun is nucleus with planets orbiting around it
* size of solar system is defined by number of planets and the distance from the sun they orbit
* Electromagnetic Radiation
* form of energy that exhibits wave like behavior as it travels through space and time
* radio waves are used to communicate
* microwaved are used to cook
* infrared waves are used as heat waves
* visible light is detected by our eyes
* ultraviolet light causes sunburns
* X-rays penetrate tissue
* Visible Light
* all of the light on earth comes from sun
* sun releases Visible light as part of electromagnetic spectrum
* the speed of light is 2.99x10^8m/s
* Wave
* a particular wave is characterized by 3 properties
* wavelength(λ)
* the distance between two consecutive peaks or two consecutive valleys
* Si unit is same as distance- m, mm, nm
* frequency
* indicates how many wave peaks are in a given time
* Si unit is- Hz
* speed
* how fast the wave is moving
* speed=wavelength x frequency
* Light
* light- energy
* electromagnetic waves- energy-carrying waves emitted by vibration electrons
* photons- particles of light
* Energy Levels
* electrons found in ground state
* when every is added to atom elections can dump to higher energy levels
* elections are considered to be in excited state
* electrons can relax down to lox we energy level and release energy as light
* scientists thought that atoms can exist on any energy levels
* because only certain photons are emitted we know that only certain energy changes are occurring
* there certain discrete energy levels that will always emit photons
* there are quantized energy levels vs. continuous energy levels
* Bohr Model of Atoms
* his model works well for Hydrogen and Helium, other experiments showed that his atomic model does not work for other
elements
* Wave Mechanical Model of the Atom
* by mid 1920s, people discovered Bohr model was incorrect
* Louis Victor de Broglie (France) and Erwin Schrodinger (Austira) suggested that light has wave and particle characteristics
* believed the electron might also exhibit both of these characteristics
* in Bohr’s model, electrons were assumed to move in a circular orbits
* wave mechanics can suggest the probability of the location of the election
* probability map or orbitals describe elections in the lowest possible energy state
* the more intense the color of a given dot, the more likely the electron can be found
* gives no information about when the electron occupies a certain point in space or how it moves
* Hydrogen
* orbital- the probability map for electrons
* electron is somewhere inside the orbital surface 90% of the time
* electron does not move around on surface
* orbital labeling rules
* number tells the principal energy level
* letter tells the shape
* Paul Exclusion Principle
* atomic orbital can hold maximum of two electrons and those two electrons must have opposite spins
* represent the spin of the electron with arrows
* Atomic Properties/Periodic Table
* metals- Lustrous appearance, ability to change shape without breaking and excellent conductivity of heat and electricity
* non-metals- typically do not have metal physical properties
* metalloids (semi-metals)- elements that exhibit both metallic and nonmetallic physical properties
* Metals
* there are Alkali metals
* there are Alkali earth metals
* there are Transition metals
* Ionization Energy
* the energy required to remove an electron from an individual atom in the gas phase
* metals tend to have low ionization energy and will give up electron easily
* non metals tend to have high ionization energy and will not give up electrons easily
* Electronegativity
* ability for an element to take an electron
* electrons orbit small positive core
* core is made up of protons and neutrons
* most of atom is empty space
* sun is nucleus with planets orbiting around it
* size of solar system is defined by number of planets and the distance from the sun they orbit
* Electromagnetic Radiation
* form of energy that exhibits wave like behavior as it travels through space and time
* radio waves are used to communicate
* microwaved are used to cook
* infrared waves are used as heat waves
* visible light is detected by our eyes
* ultraviolet light causes sunburns
* X-rays penetrate tissue
* Visible Light
* all of the light on earth comes from sun
* sun releases Visible light as part of electromagnetic spectrum
* the speed of light is 2.99x10^8m/s
* Wave
* a particular wave is characterized by 3 properties
* wavelength(λ)
* the distance between two consecutive peaks or two consecutive valleys
* Si unit is same as distance- m, mm, nm
* frequency
* indicates how many wave peaks are in a given time
* Si unit is- Hz
* speed
* how fast the wave is moving
* speed=wavelength x frequency
* Light
* light- energy
* electromagnetic waves- energy-carrying waves emitted by vibration electrons
* photons- particles of light
* Energy Levels
* electrons found in ground state
* when every is added to atom elections can dump to higher energy levels
* elections are considered to be in excited state
* electrons can relax down to lox we energy level and release energy as light
* scientists thought that atoms can exist on any energy levels
* because only certain photons are emitted we know that only certain energy changes are occurring
* there certain discrete energy levels that will always emit photons
* there are quantized energy levels vs. continuous energy levels
* Bohr Model of Atoms
* his model works well for Hydrogen and Helium, other experiments showed that his atomic model does not work for other
elements
* Wave Mechanical Model of the Atom
* by mid 1920s, people discovered Bohr model was incorrect
* Louis Victor de Broglie (France) and Erwin Schrodinger (Austira) suggested that light has wave and particle characteristics
* believed the electron might also exhibit both of these characteristics
* in Bohr’s model, electrons were assumed to move in a circular orbits
* wave mechanics can suggest the probability of the location of the election
* probability map or orbitals describe elections in the lowest possible energy state
* the more intense the color of a given dot, the more likely the electron can be found
* gives no information about when the electron occupies a certain point in space or how it moves
* Hydrogen
* orbital- the probability map for electrons
* electron is somewhere inside the orbital surface 90% of the time
* electron does not move around on surface
* orbital labeling rules
* number tells the principal energy level
* letter tells the shape
* Paul Exclusion Principle
* atomic orbital can hold maximum of two electrons and those two electrons must have opposite spins
* represent the spin of the electron with arrows
* Atomic Properties/Periodic Table
* metals- Lustrous appearance, ability to change shape without breaking and excellent conductivity of heat and electricity
* non-metals- typically do not have metal physical properties
* metalloids (semi-metals)- elements that exhibit both metallic and nonmetallic physical properties
* Metals
* there are Alkali metals
* there are Alkali earth metals
* there are Transition metals
* Ionization Energy
* the energy required to remove an electron from an individual atom in the gas phase
* metals tend to have low ionization energy and will give up electron easily
* non metals tend to have high ionization energy and will not give up electrons easily
* Electronegativity
* ability for an element to take an electron