Electron affinity - yu.edu.jo

Electron affinity - yu.edu.jo

Electron affinity Energy released or absorbed when an electron is added to a gaseous atom or ion in the ground state: X(g) + 1e- X-(g) usually exothermic process If removing an electron is endothermic, then the reversed process is exothermic. An isolated electron is brought from far away to undergo attraction to the nucleus which lowers its energy Excess energy released. e- 7e- 2e 9+ F(g) + 1e- F-(g) H=-328 kJ/mol II/ Electron attracted to nucleus F q1 q2 r2 The higher the charge exerted by nucleus (effective nuclear charge, Zeff) The closer the electron is to nucleus (smaller r) F(g) + 1e- Epotential -328 kJ/mol F (attraction) larger Potential energy of electron and atom strongly reduced Released energy larger More negative electron affinity O(g) + 1e-141 kJ/mol O-(g) F-(g) Second E.A always endothermic: O-(g) + 1e- O2-(g) H > 0 II/ n constant r EA more negative

Zeff 1A (1) 2A (2) (3)-(12) 3A (13) 4A (14) 5A (15) 6A (16) 7A (17) H -73 Zeff constant n r 8A (18) He >0 Li -60 Be 0 B -27 C -122 N 0 O -141 F -328 Ne >0 Na -53 Mg 0

Al -43 Si -134 P -72 S -200 Cl -349 Ar >0 K -48 Ca 0 Ga -30 Ge -120 As -78 Se -195 Br -325 Kr >0 Rb -47 Sr 0 In -30 Sn -120 Sb -103 Te -190 I -295 Xe >0

Cs -46 Ba 0 Tl -20 Pb -35 Bi -91 Po -180 At -270 Rn >0 EA less negative A positive electron affinity (EA) means a resistance to gaining another electron. The more negative the EA, the more strongly the atom attracts another electron. (F with an EA of -328 kJ/mol attracts electrons more strongly than O which has an EA of -141 kJ/mol). II/ Halogens (group 7A, F to At) Most negative EA values, addition of an e- leads to noble gas configuration, very favorable. Group 5A (N to Bi) filled shell discourages addition of an electron, EA values less negative than neighbors (groups 4A & 6A). Alkaline Earths (group 2A, Be to Ba) Filled s subshell discourages addition of an electron, EA values nearly zero. Noble Gases (Group 8A, He to Rn) Completely filled shell strongly discourages addition of an electron, EA values are positive. 7e8e2e- 3rd period more negative than 2nd period atoms are larger, more space for the electrons, repulsion between electrons less, more favorable 7e- 2e 17 + EA (Cl)=-348 kJ/mol EA (F)=-328 kJ/mol 9+ II/

Recently Viewed Presentations

  • Early Earth Foldable - Mr. Hester's Biology Class

    Early Earth Foldable - Mr. Hester's Biology Class

    Early Earth Foldable Fold 2 papers so that there are 4 flaps. The Titles of the for should be: Fossil Record Miller and Urey Endosymbiont Theory Redi and Pasteur Fossil Record—write the bullet below and then cut out the timeline...
  • Information Systems: A Manager's Guide to Harnessing Technology

    Information Systems: A Manager's Guide to Harnessing Technology

    Data: Raw facts and figures. Information: Data presented in a context so that it can answer a question or support decision making. Knowledge: Insight derived from experience and expertise. Organizing Data. Database: A single table or a collection of related...
  • Chapter 11 Protists - Loudoun County Public Schools

    Chapter 11 Protists - Loudoun County Public Schools

    Chapter 11 Protists Reproduction of Protists Asexual - one parent Fission- dividing of parent into 2 organisms Euglena and Amoeba Sexual - 2 parents Conjugation - swap DNA and then divide Paramecium Protista (Protists) Some are too tiny to be...
  • English 126: - Green River College

    English 126: - Green River College

    But, as is always the case, there were artists who made large-scale, full-length paintings that portrayed the noble class in richly decorative costumes with armor, embroidery, ruffs, hunting gear, weapons, and lace. These intricate designs of foliage and patterning were...
  • Statutory Instruments

    Statutory Instruments

    Case Study 2 2004 No. 1231 TOWN AND COUNTRY PLANNING, ENGLAND The Town and Country Planning (London Borough of Camden) Special Development Order 2004 Made 28th April 2004 Laid before Parliament 6th May 2004 Coming into force 31st May 2004...
  • Integrated Information Technology (IT) & Information Assurance (IA)

    Integrated Information Technology (IT) & Information Assurance (IA)

    Cybersecurity & Interoperability are Navy Imperatives. The cyber threat continues to grow exponentially; a challenge to both government and commercial cybersecurity enterprises. Ensuring critical data exchange and securing the Fleet requires a fundamental change in our approach
  • MVA - Maintaining Your Hybrid Cloud - download.microsoft.com

    MVA - Maintaining Your Hybrid Cloud - download.microsoft.com

    Accelerating Deployment with Templates. Hardware - VMM uses hardware profiles, along with a sysprepped VHD/X file to streamline deployment.VMM will create the sysprepped VHD/X for you. OS Config - Configuration of domain join, admin password, product key, but even the...
  • iupap.org

    iupap.org

    An Introduction to IUPAP. Bruce McKellar. Past President. Meeting of Council and Commission Chairs. Singapore 20180503