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Bellringer: 2/27/2017. What do you know about electrons? What do you know about light? STOTD **You will need a calculator and reference table. Updates: Monday: Start Unit 3: Light Tuesday: Atomic emission, Bohr Model , JUNIORS TAKE ACT (1 ST -3 RD ) Wednesday: Atomic Emission Dry Lab
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Bellringer: 2/27/2017 • What do you know about electrons? • What do you know about light? • STOTD **You will need a calculator and reference table Updates: Monday: Start Unit 3: Light Tuesday: Atomic emission, Bohr Model, JUNIORS TAKE ACT (1ST-3RD) Wednesday: Atomic Emission Dry Lab Thursday: QUIZ, Electron Configuration Friday: Electron Configuration Monday: Periodic Table Tuesday: Review Wednesday: TEST
Electrons in Atomsand The Periodic Table Chapters 4 and 5
Unanswered Questions • How are the electrons placed around the nucleus? • Why are the electrons NOT pulled into the nucleus? • Opposites attract • To answer these questions, scientists needed to have a new understanding of LIGHT. • Starting with Electromagnetic Radiation: • A form of energy that moves like waves through space end
Properties of Light • Visible light is a part of the Electromagnetic (EM) Spectrum • Energy that moves like a wave • Last page of Reference Tables • Wavelength (λ) • Distance between 2 identical points • Meters • Frequency (ν) • Number of waves in 1 second • Hertz (Hz) or 1/s, which is (s-1) end
Properties of Light • All EM waves travel at the Speed of Light (c) • c = 3.00 x 108 m/s • As frequency goes up: • Wavelength goes down • Energy goes up λ v E end
Electromagnetic Spectrum Visible Spectrum
Properties of Light • A gamma ray has a wavelength of 7.00 x 10-13 m. What is the frequency of this ray? • A ray has a wavelength of 5.50 x 10-7 m. What is the frequency of this ray? What type of EM wave is this? • A ray has a frequency of 7.65 x 10-2 Hz. What is the wavelength of this ray? What type of EM wave is this? • A satellite transmits on the EM Spectrum at a frequency of 9.4 x 109 Hz. What is the signal’s wavelength? • What type of wave is being transmitted? • A beam of visible light has a frequency of 4.5x1014 Hz. • What is the wavelength of this light? • What color is this light? end
Properties of Light • Light does not always act like a wave • The Photoelectric Effect • Metal gives off electrons when light shines on it • Depends on the frequency of the light • Not the amount of light • Max Planck (1900) • Matter gains/loses energy in specific amounts known as Quanta • Quantum • The minimum amount of energy that can be gained/lost Frequency Energy Planck’s Constant (6.626 x 10-34 J·s) end
Properties of Light • What is the energy of an EM wave with a frequency of 6.32 x 1026 Hz? • What is the energy of an EM wave with a frequency of 4.56 x 1015 Hz? • What is the energy of an EM wave with a frequency of 9.5 x 1030 Hz? • What energy would a beam of microwaves have if their wavelength is 5.6 x 10-2 m? (2 step problem) • A beam of visible light has a wavelength of 5.8 x 10-7 m. What is its energy and what color is it? (2 step problem) end
Bellringer: 2/27/2017 • How fast does an EM Wave travel? • How are EM waves different from each other? • Describe the relationship between v, E, and λ. • STOTD **You need a calculator and reference table today Updates: Tuesday: Atomic emission, Bohr Model, JUNIORS TAKE ACT (1ST-3RD) Wednesday: Atomic Emission Dry Lab Thursday: QUIZ, Electron Configuration Friday: Electron Configuration Monday: Periodic Table Tuesday: Review Wednesday: TEST
Properties of Light • Albert Einstein (1905) • Wave-Particle Duality • All matter and energy can act as both a wave and a particle • Photon • A particle of light • The energy of a photon depends on the frequency end
Line-Emission • Ground State: The lowest energy state of an atom • Excited State: The highest energy state of an atom • How can we see the change between states? • You can use a spectroscope • When a narrow beam of light is shined through a prism, it is separated into a series of specific wavelengths of visible light.
Emission Spectrum • Atomic Emission Spectrum • When given energy, every element gives off specific frequencies of light end
Line-Emission Spectrum O2 end
Atomic Theories- Bohr • Niels Bohr (1913) • Electrons are placed into Energy Levels • Circular orbits around the nucleus • Number of electrons in each orbit = 2n2 • Cannot be between energy Levels • Gain energy, electrons move up energy levels • To an Excited State • Release energy, electrons move down energy levels • To the Ground State • Bigger Move = More Energy end
Atomic Theories- Bohr • If an electron drops from n=3 to n=2 what would be the approximate wavelength of the light emitted? • If an electron drops from n=4 to n=1 what type of EM radiation would be produced? What is its wavelength? end
Atomic Theories- Bohr • Determine the wavelength, frequency, and type of EM wave for each of the following transitions. • n = 4 n = 1 • n = 5 n = 2 • n = 6 n = 3 end
Atomic Theories- Bohr Lets draw Li-6 p = 3 n = 3 e = 3 Lets draw H-1 p = 1 n = 0 e = 1 Lets draw Na-22 p = 11 n = 11 e = 11 Lets draw He-4 p = 2 n = 2 e = 2 end
HW • Draw Bohr Models for the following isotopes: • Be-10 • F-18 • Mg-24 • P-30 • Ar-40
Bellringer: • How can you use the Bohr Model to predict light emission? • Using your reference table determine the wavelength of light being produced from the following transitions: • n=4→n=3 • n=6 →n=3 • STOTD **You will need a calculator and your reference table today**
Bellringer: • List the electromagnetic waves in order from shortest wavelength to longest wavelength. • STOTD *
Bellringer: • List the electromagnetic waves in order from shortest wavelength to longest wavelength. • Calculate the energy of a wave that has a wavelength of 5.50 x 10-4 m. What type of EM wave is this? • STOTD
Atomic Orbitals & Quantum Numbers • From the new research scientists created the Electron Cloud Model • Nucleus with electrons orbiting in an area of high probability • Atomic Orbital • A 3-D area where you have a 95% chance of finding an electron • The Principal Quantum Number (n) • Indicates the Energy Level • 1, 2, 3, …7 • Bigger Numbers = Higher Energy • Each Energy Level has sublevels end
Atomic Orbitals & Quantum Numbers • Angular Momentum Quantum Number (l) • The Shape of each sublevel • l = 0, 1, 2, …n-1 • Labeled: s, p, d, f, g, h… p l = 1 Dumbell (Peanut) 3 orbitalsin each Energy Level s l = 0 Sphere 1 orbital in each Energy Level end
Atomic Orbitals & Quantum Numbers d l = 2 5 orbitals in each Energy Level 4 Daisy 1 Peanut in a Doughnut f l = 3 7 orbitals in each Energy Level g l = 4 9 orbitals in each Energy Level h l = 5 11 orbitalsin each Energy Level end
Electron Configuration • Electrons are arranged in a specific way according to 3 rules: • RULE 1: • Aufbau Principle • Electrons will occupy the LOWEST energy level possible • Energy Levels = 1 is the lowest • Sublevels = s < p < d < f • Sublevels “d” and “f” overlap with the next Energy Level end
Electron Configuration • RULE 2: • Pauli Exclusion Principle • ONLY 2 electrons in each ORBITAL • Electrons MUST have opposite Spins end
Electron Configuration • RULE 3: • Hund’s Rule • 1 electron in each orbital of a sublevel before you can double up Unpaired Electrons Paired Electrons end
Bellringer: • What is electron configuration? • What is an atomic orbital? • How many electrons can one orbital hold? • What does the angular momentum quantum number tell you? • STOTD
Bellringer: • What element has the following electron configuration: 1s22s22p63s23p64s23d7 • Using the electron configuration above, what is the angular momentum quantum number for the electrons furthest from the nucleus? • What is an atomic orbital? • STOTD
HW Problems from last night: • Electron Configuration for: • Lithium • Nitrogen • Sodium • Chlorine • Vanadium
Electron Configuration • Electron Configuration Notation • Instead of drawing all of the lines, use superscripts • Be • F • Mg • He • Ar • B end
Bellringer: • Orbital Notation • Draw a line and label each Energy Level and Sublevel • Add arrows to represent electrons • C • Ne • Ca • Use your Periodic Table to determine the electron configuration for the following elements in Orbital Notation: **STOTD** end
Bellringer: • What scientist created the theory of wave-particle duality? • Draw the Bohr Model for 29Si. • What is a photon? • STOTD
The Periodic Table By 1860 scientists had discovered 63 elements But no good way to organize them Scientists memorized everything This was changed by Mendeleev end
The Periodic Table Mendeleev’s Periodic Table: Elements with similar properties were placed in the same column The mass of the elements increased along each row end
The Periodic Table Mendeleev left several blank spaces in his periodic table For elements that had not been discovered yet He correctly predicted the properties of these elements based on the elements around them end
The Periodic Table The Modern Periodic Table: Based on Mendeleev’s table Similar Properties are in the Same Column Columns are called Groups Numbered 1 to 18 (from left to right) Atomic Numbersincrease going across the table Rows are called Periods Numbered 1 to 7 (from top to bottom) end
The Periodic Table • This is the full Periodic Table • As you can see it is REALLY long • Way too long to fit on a page end
The Periodic Table • To make everything fit on 1 page, the Lanthanides and Actinides are moved to the bottom end
Electron Configuration and the P.T. Energy Levels (n) 1 2 3 3 4 4 5 5 6 7 6 4 5 end
Electron Configuration and the P.T. Sublevels (l) p s d f end
Electron Configuration and the P.T. • Instead of remembering the Aufbau diagram just read the Periodic Table • Add 1 electron for each element you pass • N • Si • Ti • Mg • Mo • I end
The Periodic Table • Valence Electrons • Electrons in the highest energy level • Only thing involved in a chemical reaction • Give Elements their Chemical Properties • Group: 1 2 13 14 15 16 17 18 • # of 1 2 3 4 5 6 7 8 • Valence: end
The Periodic Table Metals Francium (Fr) is the most reactive Conduct electricity/heat Mostly solids at room temperature High melting/boiling points Can bend without breaking Nonmetals Fluorine (F) is the most reactive nonmetal Poorly conduct heat/electricity Mostly gases at room temperature Low melting/boiling points Break when bent end
The Periodic Table Metalloids Touching the stair-step line Properties between metals and nonmetals Depends on the temperature end
The Periodic Table Alkali Metals EXTREMELY REACTIVE! Transition Metals Wide Range of Properties Lanthanide and Actinide Series All are radioactive end
The Periodic Table Halogens Highly Reactive Noble Gases Extremely Unreactive THEY DO NOTHING! end