Ch. 13: Electrons in Atoms Standards: PS2B Targets: Deduce the electron arrangement for atoms and ions. Explain how the lines in an emission spectrum are related to electron energy levels.

Deduce the electron arrangement for atoms and ions. Models of Electron Arrangement J. J. Thomsen ( ) Negatively charged electrons stuck into a lump of positively charged material. Plum Pudding Model Neils Bohr ( ) Electrons arranged in circular paths, or orbits, around the nucleus. Planetary Model Erwin Schrodinger ( ) Used mathematics (quantum theory) to describe the location and energy of an electron. Quantum Mechanical Model

Deduce the electron arrangement for atoms and ions. (Just read this slide, don’t write) The Quantum-Mechanical Model. Electrons are not found at certain distances from the nucleus but are located in a region in space that is described by a set of 4 quantum numbers. The exact location and path of the electron can’t be determined. It estimates the probability of finding an electron within a certain volume of space surrounding the nucleus. Electron positions can be represented by a fuzzy cloud surrounding the nucleus (electron cloud).

Deduce the electron arrangement for atoms and ions. (write BOLD) 1 st Quantum Number: energy level (n): Describes how far the electron is from the nucleus These levels are assigned values in order of increasing energy: (n=1,2,3,4,…). The larger the number, the more energy the electrons have and are farther from the nucleus. Each of the energy levels is divided into sublevels. n=1 has 1 sublevel n=2 has 2 sublevels n=3 has 3 sublevels and so on chemwiki.ucdavis.edu

Deduce the electron arrangement for atoms and ions. (write Bold) 2 nd Quantum Number: energy sublevel (l): Describes the shape of the space the electron can be found in Sublevel Shapes: s: spherical shape; 1s, 2s, 3s, 4s, 5s … p: dumbbell-shaped; 2p, 3p, 4p, 5p … d: clover-leaf shape or double dumbbell; 3d, 4d, 5d … f: funky shape; 4f, 5f, … There are more sublevels but we won’t use them. Each energy level contains n number of sublevels n=1 has 1 sublevel (s) n=2 has 2 sublevels (s,p) n=3 has 3 sublevels (s,p,d) n=4 has 4 sublevels (s,p,d,f) n=5 has 5 sublevels (s,p,d,f,?) chemwiki.ucdavis.edu

Deduce the electron arrangement for atoms and ions. (Write BOLD) 3rd Quantum number: orbitals (m) Describes how many different arrangements in space the sublevels can have. Every s sublevel has 1 position Every p sublevel has 3 positions Every d sublevel has 5 positions Every f sublevel has 7 positions 1s has 1 position; 2p has 3 positions, 4p has 3 positions; 3d has 5 positions; 5f has 7 positions Meta-synthesis.com

Deduce the electron arrangement for atoms and ions. (write BOLD) 4th quantum number: spin (s) Any orbital can only have a maximum of two electrons, each having opposite spins. (this is like the pigs in the “Hog Hilton”) Every s sublevel can only have a maximum of 2 electrons Every p sublevel can only have a maximum of 6 electrons Every d sublevel can only have a maximum of 10 electrons Every f sublevel can only have a maximum of 14 electrons Chegg.com

Deduce the electron arrangement for atoms and ions. (Write BOLD) Order of Electron “Fill-up” This order must be followed every time 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p Pass out Electron Road Map

Energy Level Summary n = energy level l = sublevel m =orbital s = spin 4p    4 = energy level p = sublevel; there are 3 orbitals/rooms available 6 = number of electrons; 2 electrons fit in each orbital

Deduce the electron arrangement for atoms and ions. Diagramming Electron Arrangement There are three methods for diagramming electron Arrangement Electron Configuration Orbital Filling Diagram Electron Dot Diagram

Deduce the electron arrangement for atoms and ions. Electron Configuration Start with 1s and follow the order until all the electrons in the atom have a place. Draw electron configurations for the following elements: H1s 1 Be1s 2 2s 2 O1s 2 2s 2 2p 4 Al Ca Zr

Deduce the electron arrangement for atoms and ions. Electron Configuration Start with 1s and follow the order until all the electrons in the atom have a place. Draw electron configurations for the following elements: H1s 1 Be1s 2 2s 2 O1s 2 2s 2 2p 4 Al1s 2 2s 2 2p 6 3s 2 3p 1 Ca1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 Zr1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 2 Chemistry: Electron Practice 1

Deduce the electron arrangement for atoms and ions. Orbital Filling 1. Determine number of electrons in the atom. 2. Draw a box or a line for each orbital. 3. Place arrows to denote electrons. Maximum of 2 electrons per box. The first arrow is pointing up, the second arrow is pointing down to represent opposite spins. Within a sublevel, each orbital must get an electron before the second electron is added How many electrons do each of the following elements have? H Be O

Deduce the electron arrangement for atoms and ions. Orbital Filling 1. Determine number of electrons in the atom. 2. Draw a box or a line for each orbital. 3. Place arrows to denote electrons. Maximum of 2 electrons per box. The first arrow is pointing up, the second arrow is pointing down to represent opposite spins. Within a sublevel, each orbital must get an electron before the second electron is added How many electrons do each of the following elements have? H: 1 e - Be: 4 e - O: 8 e -

Deduce the electron arrangement for atoms and ions. Orbital Filling 1. Determine number of electrons in the atom. 2. Draw a box or a line for each orbital. 3. Place arrows to denote electrons. Maximum of 2 electrons per box. The first arrow is pointing up, the second arrow is pointing down to represent opposite spins. Within a sublevel, each orbital must get an electron before the second electron is added Draw orbital filling diagrams for the following atoms. H__ 1s Be __ __ 1s 2s O __ __ __ __ __ 1s 2s 2p

Deduce the electron arrangement for atoms and ions. Orbital Filling 1. Determine number of electrons in the atom. 2. Draw a box or a line for each orbital. 3. Place arrows to denote electrons. Maximum of 2 electrons per box. The first arrow is pointing up, the second arrow is pointing down to represent opposite spins. Within a sublevel, each orbital must get an electron before the second electron is added Draw orbital filling diagrams for the following atoms. H__ 1s Be __ __ 1s 2s O __ __ __ __ __ 1s 2s 2p

Deduce the electron arrangement for atoms and ions. Orbital Filling Draw a box or line for each orbital. Place arrows to denote electrons. Maximum of 2 electrons per box. The first arrow is pointing up, the second arrow is pointing down to represent opposite spins. Within a sublevel, each orbital must get an electron before the second electron is added Draw orbital filling diagrams for the following atoms. Al Ca Zr

Deduce the electron arrangement for atoms and ions. Orbital Filling Draw a box or circle or line for each orbital. Place arrows to denote electrons. Maximum of 2 electrons per box. The first arrow is pointing up, the second arrow is pointing down to represent opposite spins. Within a sublevel, each orbital must get an electron before the second electron is added Draw orbital filling diagrams for the following atoms. Al __ __ __ __ __ __ __ __ __ 1s 2s 2p 3s 3p Ca __ __ __ __ __ __ __ __ __ __ 1s 2s 2p 3s 3p4s

Deduce the electron arrangement for atoms and ions. Orbital Filling Draw a box or circle or line for each orbital. Place arrows to denote electrons. Maximum of 2 electrons per box. The first arrow is pointing up, the second arrow is pointing down to represent opposite spins. Within a sublevel, each orbital must get an electron before the second electron is added Draw orbital filling diagrams for the following atom. Zr __ __ __ __ __ __ __ __ __ 1s 2s 2p 3s 3p __ __ __ __ __ __ __ __ __ 4s 3d 4p __ __ __ __ __ __ 5s 4d Go to Electron Configuration Practice 2 Handout

Deduce the electron arrangement for atoms and ions. Electron Dot Diagram Using the symbol for the element, place dots around the symbol corresponding to the outer energy level s & p electrons (valence electrons). Will have from one to eight dots in the dot diagram. Draw electron dot diagrams for the following atoms H Be O Al Ca Zr H Be O Go over electrons on Periodic table

Deduce the electron arrangement for atoms and ions. Electron Dot Diagram Using the symbol for the element, place dots around the symbol corresponding to the outer energy level s & p electrons. Will have from one to eight dots in the dot diagram. Draw electron dot diagrams for the following atoms Al Ca Zr

Deduce the electron arrangement for atoms and ions. Electron Dot Diagram Using the symbol for the element, place dots around the symbol corresponding to the outer energy level s & p electrons. Will have from one to eight dots in the dot diagram. GO TO ELECTRON DOT DIAGRAM HO Draw electron dot diagrams for the following atoms Al Ca Zr

Deduce the electron arrangement for atoms and ions. Write electron configuration, orbital filling diagrams, and electron dot diagrams. ClSnTbKr Go to electron arrangement of ten elements

Ion Configuration Review ions and pass out periodic table to review group number and ion charge.

Deduce the electron arrangement for atoms and ions. Ion Electron Configurations What are ions? Atoms with a charge (more or less e-) Anion: atom with a negative charge (gained e-) Cation: atom with a positive charge (lost e-) How will this change electron configurations? It will add or subtract electrons

Deduce the electron arrangement for atoms and ions. Electron Configurations H1s 1 Be1s 2 2s 2 O1s 2 2s 2 2p 4 Al 1s 2 2s 2 2p 6 3s 2 3p 1 P 1s 2 2s 2 2p 6 3s 2 3p 3 Ion Electron Configurations H + 1s 0 Be 2+ 1s 2 O 2- 1s 2 2s 2 2p 6 Al 3+ 1s 2 2s 2 2p 6 P 3- 1s 2 2s 2 2p 6 3s 2 3p 6

Deduce the electron arrangement for atoms and ions. Ion Electron Configurations Practice: Write the electron configurations for the following ions: Li +, I -, Ra 2+, S 2-, N 3-

Deduce the electron arrangement for atoms and ions. Ion Orbital Filling Orbital Filling diagrams for atoms: Al __ __ __ __ __ __ __ __ __ 1s 2s 2p 3s 3p Ca __ __ __ __ __ __ __ __ __ __ 1s 2s 2p 3s 3p4s Orbital Filling for ions: Al 3+ __ __ __ __ __ __ __ __ __ 1s 2s 2p 3s 3p Ca 2+ __ __ __ __ __ __ __ __ __ __ 1s 2s 2p 3s 3p 4s

Ions are formed when atoms gain or lose electrons Sodium configuration: 1s 2 2s 2 2p 6 3s 1 or __ __ __ 1s 2s 2p 3s If Na loses one electron then it would end in 2s 2 2p 6 and be stable. Then sodium has 11 protons (11+), but only 10 electrons (10-) so it acquires a charge of 1+ and becomes the sodium ion, Na +. In order for it to lose an electron, something has to gain an electron Electron Dot Diagram for Cations

Electron Dot Diagram for Anions Ions are formed when atoms gain or lose electrons Chlorine configuration: 1s 2 2s 2 2p 6 3s 2 3p 5 or __ __ __ __ __ __ __ __ __ 1s 2s 2p 3s 3p If Cl gains one electron then it would end in 3s 2 3p 6 and be stable. Then chlorine has 17 protons (17 + ), and 18 electrons (18 - ) so it acquires a charge of 1 - and becomes the chloride ion, Cl -. It will gain the electron from the sodium.

Explain how the lines in an emission spectrum are related to electron energy levels. Electromagnetic Spectrum Shows all electromagnetic waves by frequency and wavelength Visible light is the portion we can see (ROY G BIV) UV, x-rays, and gamma rays are more energetic than visible light (smaller wave length) Radio, TV, radar, and infrared rays are less energetic than visible light (longer wave length)

Explain how the lines in an emission spectrum are related to electron energy levels. Continuous Spectrum Emission showing a continuous range of wavelengths and frequencies Line Spectrum Emission of specific elements showing a series of discrete lines GO TO MOVIE

Explain how the lines in an emission spectrum are related to electron energy What is happening? When atoms absorb energy, electrons move into higher energy levels. The atom becomes unstable so the electrons then lose energy by emitting light, or photons, when they return to lower energy levels.

Explain how the lines in an emission spectrum are related to electron energy Atomic Spectra and Frequency Each line of light in an element’s atomic spectra is a specific frequency of light emitted by the atoms of that element.

Explain how the lines in an emission spectrum are related to electron energy Different elements have different atomic spectra because their electrons make different energy transitions between their energy levels

Explain how the lines in an emission spectrum are related to electron energy Hydrogen Line Spectrum (must know this one!) Purple, Blue, Green, Red Note the spacing of the lines! Draw this in your notes!

Atomic Spectra and Electron Energy Each line of light is equal to a specific amount of energy given off as a result of electrons moving from higher to lower energy levels.

Atomic Spectra The frequencies of light emitted by an element separate into discrete lines to give the atomic emission spectrum of the element. MercuryNitrogen *The light emitted by an electron moving from a higher to a lower energy level has a frequency directly proportional to the energy change of the electron. When light from a helium lamp passes through a prism, discrete lines are produced.

An Explanation of Atomic Spectra In the Bohr model, the lone electron in the hydrogen atom can have only certain specific energies. –When the electron has its lowest possible energy, the atom is in its ground state. –Excitation of the electron by absorbing energy raises the atom from the ground state to an excited state. –A quantum of energy in the form of light (photon) is emitted when the electron drops back to a lower energy level.

Hydrogen spectra Exact amounts of energy are absorbed by H as electrons move to higher energy levels The same amount of energy absorbed is emitted as the electrons fall back to the lower energy levels The energy is emitted in the form of light with a frequencies that contain the energy being lost as the electrons move to the lower levels