Notes CH 5 Electron Configurations Chemistry Sra. Bartlett U5 Electrons in Atoms Notes CH 5 Electron Configurations telling electrons where they can go!!

Electrons.. Where are they? Chemistry Sra. Bartlett U5 Electrons in Atoms Electrons.. Where are they? And why do we need to know? The chemical behavior of an element is determined by the number of electrons and how they are arranged.

Chemistry Sra. Bartlett U5 Electrons in Atoms Bohr’s model Helped explain why elements give off certain colors of light (excited electrons jumping to lower energy levels) Electrons travel in specific energy “orbits” but not in between them. 3rd Electron can be here 2nd 1st But not here

Review…Bohr’s model of the atom Chemistry Sra. Bartlett U5 Electrons in Atoms Review…Bohr’s model of the atom Each level has a certain number of e- 1st = 2 2nd = 8 3rd = 18 (or 8) 4th = 32 (or 18 or 8) 5th = 32 (or 18 or 8) 6th = 18 (or 8) 7th = 8 **Note= last level cannot have more than 8 valence e- Energy levels nucleus

Bohr models of various atoms. Chemistry Sra. Bartlett U5 Electrons in Atoms Bohr models of various atoms. Draw (or write) the Bohr sequence for Calcium (20) Give the # of valence electrons (last level) Tell if will lose e- (like metals, have less than 4) or gain e- (like non-metals, have more than 4) or metalloids (either gain or lose) Give the isotope symbol

Bohr models of various atoms. Chemistry Sra. Bartlett U5 Electrons in Atoms Bohr models of various atoms. Draw (or write) the Bohr sequence for Bromine Give the # of valence electrons (last level) Tell if will lose e- (like metals, have less than 4) or gain e- (like non-metals, have more than 4) or metalloids (either gain or lose) Give the isotope symbol

Chemistry Sra. Bartlett U5 Electrons in Atoms Example For all the element Bromine (35): 1) Draw (or write) the Bohr sequence 2) Give the # of valence electrons 3) Tell if will lose e- (like metals) or gain e- (like non-metals) 4) Give the ion symbol and charge 2 – 8 – 18 - 7 7 Will gain one electron 80 35 Br -1

Chemistry Sra. Bartlett U5 Electrons in Atoms Question Why do elements give off different colors of light when heated? (need to know for LAB on Friday) Some of the electrons (ground state) gain enough energy from the heat to jump up to a higher energy level (excited state). They are unstable here so they jump back to a lower level and give off the energy gained as photons. The photon’s energy determines the frequency (and color) of light.

Flame tests and Spectra Chemistry Sra. Bartlett U5 Electrons in Atoms Flame tests and Spectra Each element has a characteristic pattern of light that it emits. This can be used as a “fingerprint” for identification.

Chemistry Sra. Bartlett U5 Electrons in Atoms Niels Bohr’s Atomic model Yes! It’s Bohring! http://videos.howstuffworks.com/hsw/5787-niels-bohrs-atomic-model-video.htm

Assignment = Simple atomic models a. Bohr’s model b. isotope symbol c. charge For these elements: S, As, Sr, Ar, Cl, Ag 2. Pg 145 # 10, 12-14 (show details for calculations)

Modern views of the Atom Chemistry Sra. Bartlett U5 Electrons in Atoms Modern views of the Atom Electrons can act as particles and sometimes as waves (dual nature) Electrons travel in paths that look like clouds. The size and shape of these depend on how much energy the electrons have. The 4 quantum numbers describe the location of the electrons: Principal QN (symbol “n”) refers to the number of energy levels and indicates the relative size and energies in the atomic orbitals.

Chemistry Sra. Bartlett U5 Electrons in Atoms Secondary or angular QN (symbol “l” ) indicates the sublevel (s, p, d, or f) Magnetic QN (symbol “m”) indicates the orbital the electron is in (px, py or pz) Spin QN (symbol “s” ) indicates the direction the electron is spinning (left or right) There are 7 energy levels divided into different sublevels which are divided into orbitals. An orbital is the space where two electrons travel. They have the shape of the sublevel but different orientations. Sublevels: s = 2 e- max p = 6 e- d = 10 e- f = 14 e-

Chemistry Sra. Bartlett U5 Electrons in Atoms “p” =

Chemistry Sra. Bartlett U5 Electrons in Atoms Shape of d

Chemistry Sra. Bartlett U5 Electrons in Atoms Shape of f

Chemistry Sra. Bartlett U5 Electrons in Atoms Mind Blowing!! Just read Just imagine an atom with for example 92 electrons like Uranium. All are whizzing around the nucleus at the speed of light in different shaped paths. Video orbitals! http://www.youtube.com/watch?v=K-jNgq16jEY&feature=related

Electron configuration (long form) Chemistry Sra. Bartlett U5 Electrons in Atoms Electron configuration (long form) This gives MORE information about predicting properties. The placement of an elements electrons is written as: 4th Energy level 6 electrons 4p6 These add up to total # of e- Sublevel p 1s2, 2s2, 2p6, 3s2, 3p6 How many total electrons? What element is it?

Chemistry Sra. Bartlett U5 Electrons in Atoms There are rules! Aufbau rule: Electrons occupy the lowest energy orbitals first. Hund’s rule: States that single electrons must occupy separate orbitals before pairing up. Pauli Exclusion Principle: No two electrons in an atom have all 4 quantum numbers the same. One quantum number must be different. Aka  SPIN!

Chemistry Sra. Bartlett U5 Electrons in Atoms The “Arrow” Diagram Electrons arrange themselves in orbitals of increasing energy. Examples: N Al K Br Ag This is on page 160. s = 2 p = 6 d= 10 f = 14

Chemistry Sra. Bartlett U5 Electrons in Atoms Take sulfur for example. It has an atomic number of 16, so it has 16 electrons. Let’s put these in order. 1s2, 2s2, 2p6, 3s2, 3p4 Valence e-? _____ on level ____ How many e- lost/gained? _______ Charge of ion? _______ Check it! it should be in group 6 and on period 3 ……is it?

Chemistry Sra. Bartlett U5 Electrons in Atoms Practice Write the electron configuration (long form) for: Arsenic ____ electrons And for arsenic’s ion? (As3-) 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p3

Chemistry Sra. Bartlett U5 Electrons in Atoms Practice Write the electron configuration (long form) for: Silver ____ electrons And for silver ion? Hint: it loses one e-) 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6 , 5s2 , 4d9

HW pg. 160 #21 & 22 and WS

Chemistry Sra. Bartlett U5 Electrons in Atoms Bellringer Turn in HW pg 160 (21, 22) A) Write the long-form electron configuration for V (23) B) tell how many valence e- it has C) give the ionic charge 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d3 ; 2; 2+

Chemistry Sra. Bartlett U5 Electrons in Atoms Bellringer 2 Which QN symbol means “main energy level”? Which 4 symbols means “sublevel”? Write the long configuration for Se (34) How many valence electrons are there? What will the charge of the ion be? n s, p, d, f 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p4 6 2-

Electron configuration Shorthand version (Noble gas version) Chemistry Sra. Bartlett U5 Electrons in Atoms Electron configuration Shorthand version (Noble gas version) Ex Silver = [1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6 ], 5s2 , 4d9 Take the previous Noble Gas and substitute [Kr], 5s2 , 4d9 Or do directly from PT……

Chemistry Sra. Bartlett U5 Electrons in Atoms Copy or memorize… or Google → ← 7p → “f” before “d” d (n-1) and f (n-2)

Chemistry Sra. Bartlett U5 Electrons in Atoms More…. Oxygen And O2- ?? Arsenic Aluminum And Al3+ ?? Europium

Chemistry Sra. Bartlett U5 Electrons in Atoms More Practice Fe 3+ F1- Na1+ N 3-

Chemistry Sra. Bartlett U5 Electrons in Atoms Rules? …..What rules? Electrons can behave as a particle but also have wavelike behavior (dual-nature by DeBroglie) Electrons will be in the lowest available energy position first. (Aufbau rule) Electrons will be in separate orbitals (same energy) before pairing up. (Hund’s rule) Electrons will orient themselves to have opposite spins if in same orbital. (Pauli rule) What??? Let’s try applying this…..

Chemistry Sra. Bartlett U5 Electrons in Atoms Orbital diagrams We use boxes to indicate the orbitals And arrows to indicate each electron 1s 2s 2p 3s 4d

Chemistry Sra. Bartlett U5 Electrons in Atoms Practice Let’s do oxygen (8e-) So…it has 2 unpaired electrons to use for bonding with other elements. And now aluminum (13 e-) 1s 2s 2p 3s 3p 1s 2p 3s 3p 2s

Chemistry Sra. Bartlett U5 Electrons in Atoms More Let’s do Neon (10 e-) And now chlorine (18 e-) 1s 2s 2p 3s 3p 1s 2p 3s 3p 2s

Chemistry Sra. Bartlett U5 Electrons in Atoms And Vanadium Selenium

Chemistry Sra. Bartlett U5 Electrons in Atoms Bellringer Turn in Homework What is the long form electron configuration for sulfur? See pg 160 How many valence electrons does it have and on what level? How many e- does it need to have a complete valence level? What is the short form and orbital diagram for Te (52)? What is wrong with this? [Ar] 4s2, 3d6 , 4p3

Practice Pd Ge Pb Bohr model long form Short form Orbital diagram Valence e- Pd Ge Pb

Homework At (85) K(19) Se (34) P(15) Bohr model long form Short form Orbital diagram Valence e- At (85) K(19) Se (34) P(15)

Chemistry Sra. Bartlett U5 Electrons in Atoms Video http://www.youtube.com/watch?v=xH1k1dtgiVY

Electron Dot Diagrams Only show valence electrons Examples:

Chemistry Sra. Bartlett U5 Electrons in Atoms Assignment Pg 167 (Glencoe) # 81, 85, 86, 87, 90

Chemistry Sra. Bartlett U5 Electrons in Atoms To turn in! Write the: a) short electron configuration. b) # of valence e c) # e- lost/gained d) charge of ion iodine 5. helium hafnium 6. boron francium 7. yttrium xenon 8. tin

Chemistry Sra. Bartlett U5 Electrons in Atoms Exit slip For the element Phosphorous (P) and Bromine (Br) Write the: a) short electron configuration. b) # of valence e c) # e- lost/gained d) charge of ion e) orbital diagram

Chemistry Sra. Bartlett U5 Electrons in Atoms Bellringer What is the long form electronWhich symbol means “main energy level”? Which symbol means “sublevel”? Which symbol means “number of electrons”? How many valence electrons are there? What will the charge of the ion be? [Ar] 4s2, 3d10 , 4p3 3 or 4 s, p or d 2, 3 or 10 5 3-

Chemistry Sra. Bartlett U5 Electrons in Atoms Bellringer What symbol is used in orbital diagrams to show one electron? What rule says that electrons will occupy the lowest energy orbitals first? Who first stated that electrons can behave both as a particle and as a wave? What do we call the distance on a wave for a complete cycle? What do we call the height (energy) of a wave? An arrow Aufbau DeBroglie Wavelength Amplitude

Chemistry Sra. Bartlett U5 Electrons in Atoms To turn in! Write the: a) Bohr sequence (ex 2-8-3) b) long electron configuration. c) # of valence e d) # e- lost/gained, charge of ion Palladium 5. Argon Indium 6. Molybdenum Gadolinium 7. Polonium Dysprosium 8. Radium

EMR (electromagnetic radiation) Chemistry Sra. Bartlett U5 Electrons in Atoms EMR (electromagnetic radiation) All wavelengths = from gamma rays (very short=high energy) to radio and TV (long=low energy). All types of EMR travel at the speed of light Are emitted when excited electrons jump to lower energy levels. A “piece” or quantum of EMR is called a photon.

Chemistry Sra. Bartlett U5 Electrons in Atoms Review EMR waves or crests A Solving problems Show all your work, write the equation and be sure to indicate your units c= v and E­photon = h v speed of light is c=3.00 x 108 m/s Planck’s constant is h = 6.626 x 10-34J s What is the wavelength of electromagnetic radiation with a frequency of 8.77 x 1014 Hz? What is the frequency of light that has a wavelength of 400. nm?

More Calculate the frequency for yellow light See handout 600 nm = 600 x -9 m Calculate the frequency for a bar-code laser. 660 nm = 660 x 10 -9 m Calculate the energy for an X-ray photon (3.88 x 10 17 Hz) 5.00 x 10 14 1/s 4.55 x 10 14 1/s 2.57 x 10 -16 J