Document Sample

Isotope Formulae, Quantum Numbers & Electron Configurations …pretty lofty stuff Isotope Formulae • Provide element’s symbol • Mass number – mass# = #p+ + #n – written as a superscript to the left • Atomic number – atomic# = #p+ or #e- – written as a subscript to the left Isotope Formulae Mass# Atomic# X Carbon has two naturally occurring isotopes: carbon-12 and carbon-13 12 13 6 C 6 C Isotope Formulae Give the isotope formula for each of the following: 3 1. Hydrogen with 2 neutrons 1 H 18 2. Fluorine with 9 neutrons 9 F 235 3. Uranium with 143 neutrons 92 U Valence Electron(s) • The electron(s) farthest from the nucleus or in the outermost energy level. Aufbau Principle • Comes from German word meaning “to build” • Electrons will occupy lower energy orbitals first Pauli Exclusion Principle • An atomic orbital can hold at most two electrons. • If an atomic orbital holds two electrons, they must have opposite spins. Hund’s Rule • When filling atomic orbitals of equal energy, place electrons with parallel spins in the orbitals first. Then, place the oppositely spinning electrons in to the orbitals. Quantum Numbers • Similar to your address • Describe where electrons live within an atom • Four quantum numbers for every electron of every atom Quantum Numbers • Principal (n) – Describes the energy level in which the electron lives – May be any positive integer – Thus, 1, 2, 3, etc. Quantum Numbers • Azimuthal or angular mometum (l ) – Azimuth means course or bearing – Describes the shape of the pathway that the electron takes or the shape of the atomic orbital – May be any integer from zero to (n- 1)…it’s dependent on “n” – Thus, when n=1, l can only be 0 Quantum Numbers • Magnetic (ml ) – Describes the orientation of the atomic orbital in 3-D space – May range from -l to +l …it’s dependent on “l” which is dependent on “n” – Thus, when n=1, l can only be 0, and ml can only be 0 – When n=2, l can be 0 or 1, and when l is 1, ml can be –1, 0, or +1…or three places in space Quantum Numbers • Spin (ms ) – Describes the spin of the electron – May be either –½or +½, it’s dependent upon none of the other quantum numbers – Thus, when n=1, l can only be 0, and ml can only be 0, but ms can be either –½or +½ The Quantum Numbers name symbol values Principal Quantum any positive integer n Number from 1 to infinity Azimuthal Quantum l any integer from 0 to n- Number 1 Magnetic Quantum ml any integer from -l to +l Number Spin Quantum ms - ½ or + ½ Number Quantum Numbers • What are the four quantum numbers of hydrogen’s electron? n=1 l=0 ml = 0 ms = –½ Quantum Numbers • What are the four quantum numbers of all of boron’s five electrons? n=1 n=1 n=2 n=2 n=2 l=0 l=0 l=0 l=0 l=1 ml = 0 ml = 0 ml = 0 ml = 0 ml = -1 ms = –½ ms = +½ ms = -½ ms = +½ ms = -½ Quantum Numbers • What are the four quantum numbers of sodium’s valence electron? n=3 l=0 ml = 0 ms = –½ Electron Configurations • Also describe where electrons live within an atom • It’s like a translation of quantum numbers. • They give the energy level, atomic orbital, and number of electrons residing in the orbital and energy level. Electron Configurations • Energy level – May be any positive integer – Just like the principal quantum number Electron Configurations • Atomic Orbital or Sublevel – Represented by letters: s, p, d, f – Translates azimuthal number and magnetic number – s is the same as l = 0 – p is the same as l = 1 – d is the same as l = 2 – f is the same as l = 3 Electron Configurations • Number of Electrons – in either an atomic orbital or a sublevel – max of 2 in the s sublevel – max of 6 in the p sublevel – max of 10 in the d sublevel – max of 14 in the f sublevel Electron Configurations • Use the periodic table to guide you in writing electron configurations. • Find the link between 2,6,10, and 14 and the periodic table. Electron Configurations • What are the four quantum numbers of hydrogen’s electron? What is the electron configuration of hydrogen? # of n=1 energy 1s 1 electrons level l=0 ml = 0 sublevel/ orbital ms = –½ Electron Configurations • Write the e- configurations of the next 9 elements (through Ne). He…1s2 Li… 1s22s1 Look at the sum of the superscripts… Be… 1s22s2 B… 1s22s22p1 Electron Configurations C… 1s22s22p2 N… 1s22s22p3 O… 1s22s22p4 F… 1s22s22p5 Ne…1s22s22p6 Electron Configurations • Shorthand configurations are written by assuming that you can let the symbol of the noble gas preceding the valence electrons represent the e- configuration to that point. Electron Configurations …shorthand He…1s2 Li… [He]2s1 Be… [He]2s2 B… [He]2s 22p1 C… [He]2s 22p2 Electron Configurations …shorthand N… [He]2s22p3 O… [He] 2s22p4 F… [He] 2s22p5 Ne…[He] 2s22p6 Electron Configurations …shorthand Na… [Ne]3s1 Si… [Ne] 3s23p2 Cl… [Ne] 3s23p5 Ar… [Ne] 3s23p6 Electron Configurations …shorthand Ca…[Ar]4s2 Sc… [Ar] 4s23d1 Mn…[Ar] 4s 23d5 Se… [Ar] 4s23d104p4 Electron Configurations …shorthand I… [Kr] 5s24d105p5 La… [Xe] 6s25d1 Ce…[Xe] 6s 25d14f1 Hg…[Xe] 6s24f145d10 Exceptional Electron Configurations…shorthand Cr… [Ar] 4s23d4 [Ar] 4s13d5 Cu…[Ar] 4s23d9 [Ar] 4s13d10 Mo…[Kr] 5s 24d4 [Kr] 5s14d5 Ag…[Kr] 5s24d9 [Kr] 5s14d10 Orbital Diagrams • Show the electron configuration while illustrating the Aufbau Principle, Pauli Exclusion Principle, and Hund’s Rule • Place energy on the y-axis • Use lines to represent orbitals • Use up and down arrows to indicate spin Orbital Diagrams (template) 3px 3py 3pz 3s E 2px 2py 2pz 2s 1s Orbital Diagram for H 3px 3py 3pz 3s E 2px 2py 2pz 2s 1s Orbital Diagram for He 3px 3py 3pz 3s E 2px 2py 2pz 2s 1s Orbital Diagram for Be 3px 3py 3pz 3s E 2px 2py 2pz 2s 1s Orbital Diagram for C 3px 3py 3pz 3s E 2px 2py 2pz 2s 1s Orbital Diagram for O 3px 3py 3pz 3s E 2px 2py 2pz 2s 1s Orbital Diagram for P 3px 3py 3pz 3s E 2px 2py 2pz 2s 1s Wrap-Up • Write the 4 quantum numbers for each of nitrogen’s 7 electrons. • Write the electron configuration for nitrogen. • Write the orbital diagram for nitrogen.

DOCUMENT INFO

Shared By:

Categories:

Tags:

Stats:

views: | 13 |

posted: | 3/23/2012 |

language: | Latin |

pages: | 41 |

OTHER DOCS BY yurtgc548

How are you planning on using Docstoc?
BUSINESS
PERSONAL

By registering with docstoc.com you agree to our
privacy policy and
terms of service, and to receive content and offer notifications.

Docstoc is the premier online destination to start and grow small businesses. It hosts the best quality and widest selection of professional documents (over 20 million) and resources including expert videos, articles and productivity tools to make every small business better.

Search or Browse for any specific document or resource you need for your business. Or explore our curated resources for Starting a Business, Growing a Business or for Professional Development.

Feel free to Contact Us with any questions you might have.