Documents about Effective Nuclear Charge

  • 15 Pages


    Penn State, CHEM 110

    Excerpt: ... Periodic Properties of the Elements (Lecture 7) Row called a Period Column called a Group or Family Electron Configuration and the Periodic Table Location on the Periodic Table is related to electron configuration Valence orbitals are those that contain the outer shell of electrons Electrons in valence orbitals are those that are involved in bonding. Elements in the same Group (column) of the Periodic Table contain the same number of electrons in their valence orbitals. (H) Li Na K Rb 1s1 [He]2s1 [Ne]3s1 [Ar]4s1 [Kr]5s1 Effective Nuclear Charge Electrons in inner core shield outer electrons from full positive charge of nucleus. The actual nuclear charge felt by any given electron is called the effective charge (Zeff) Zeff can be approximated by the equation: Zeff = Z S; Z = nuclear charge (i.e. number of protons) S = screening constant (approximated as number of core electrons between elecron of interest) Electrons of same n value dont screen as well. Trends in Effective Nuclear Charge ...

  • 2 Pages

    chem 141 F07 Chapter 8 Study Sheet

    Emory, CHEM 141

    Excerpt: ... bering system. 1 Modified from Change, R. Chemistry 6/e 1998 p.287. DEFINITIONS You should have a working knowledge of at least these terms and any others used in lecture. Covalent radius Metallic radius Ionic radius Diamagnetic Paramagnetic Ionization energy Electron affinity Periodic law Electron configuration Effective nuclear charge Isoelectronic Aufbau principle Transition elements Main group s-, p-, d-, f-block elements Lanthanides Actinides Halogens Noble gases Calcogens Alkali metals Alkaline earth Law of octaves Law of triads ...

  • 1 Pages


    SUNY Albany, CHM 120

    Excerpt: ... Key Points for Study Chapter 7: Periodic Properties of Elements I. Key points to pay attention: How position on the periodic table and electron configurations can be used to highlight periodic properties, not so much about the absolute values but rather, the trend or the periodic pattern. You may find the descriptive chemistry/group trends a bit overwhelming at first. However, the periodic table IS REALLY an organizational tool; it will help you recall chemical facts. The sign convention for electron affinities should not be confused. II. Understand clearly the terms and concepts summarized at the end of the chapter in the book. The following are some specific points I wish to emphasize, and you must handle these concepts and skills: 1. Effective nuclear charge . Know how to calculate effective nuclear charge given an element (think about a more basic question: why is it that we need to introduce the effective nuclear charge - see the following periodic properties) 2. Be able to predict the size of i ...

  • 4 Pages

    Lecture 6 NotesThe Periodic Table and Atomic Co...

    University of Texas, CH 53750

    Excerpt: ... iscussion. Electronic shielding will be employed to explain the atomic trends that we will discuss below. Think of the atom as a rock concertthere is a stage with the band (nuclear protons) and rows of seats (electronic shells) with screaming fans (the electrons). Just as in a rock concertthe closest row can be thought of as the best seat in the house (they get the full experience of the show) while the back row isnt very good (too many screaming fans blocking the view). This is analogous to atomselectrons in the innermost shell feel the full nuclear force while electrons in the outermost shell will feel a somewhat reduced nuclear force (called the effective nuclear charge (E.N.C.) because other electrons lie in the intervening shells and block a portion of the nucleus pull. It is important to note that electrons in your same shell will not shield other electrons in the same shell (fans in the same row as you will in general not hinder your ability to enjoy the concert). So ...

  • 70 Pages


    SUNY Buffalo, CHE 101

    Excerpt: ... o allowed values of ml of -1, 0, and +1.) The orbitals are dumbbell shaped. As n increases, the p-orbitals get larger. All p-orbitals have a node at the nucleus. Chapter 5 48 Representation of Orbitals The p Orbitals Chapter 5 49 Representation of Orbitals The d and f Orbitals There are 5 d- and 7 f-orbitals. Three of the d-orbitals lie in a plane bisecting the x-, yand z-axes. Two of the d-orbitals lie in a plane aligned along the x-, y- and z-axes. Four of the d-orbitals have four lobes each. One d-orbital has two lobes and a collar. Chapter 5 50 Representation of Orbitals The d Orbitals Chapter 5 51 Orbitals in Many Electron Atoms Orbitals of the same energy are said to be degenerate. For n 2, the s- and p-orbitals are no longer degenerate because the electrons interact with each other. Therefore, the Aufbau diagram looks slightly different for many-electron systems. Effective Nuclear Charge Effective nuclear charge is the charge experienced by an electron ...

  • 3 Pages

    Study Guide Exam 3

    UC Riverside, CHEM 1A

    Excerpt: ... be able to predict relative sizes. Terms: All terms except: effective nuclear charge , penetration, and amphoteric. Study Guide Exam III.doc Page 2 ...

  • 35 Pages


    SUNY Albany, CHM 120

    Excerpt: ... se nodes? Atomic Orbitals of Hydrogen-like Atoms Hydrogen-like Atoms For an atom or ion with one electron orbiting a nucleus of charge Z The orbital energies are given by En = -Z2hcRH(1/n2) where n is the principal quantum number (i.e., n = 1, 2, 3, .), and RH is the Rydberg constant = 1.096776 107 m-1. Hydrogen and Helium Ground States Hydrogen atom Helium positive ion Helium atom Orbitals in Many Electron Atoms Effective nuclear charge is the charge experienced by an electron in an orbital on a many-electron atom. The effective nuclear charge is less than the charge on the nucleus because of the shielding effect of inner electrons. Electrons in outer orbitals are attracted to the nucleus, but repelled by electrons in inner orbitals that screen them from the nuclear charge. As the average number of screening electrons (S) increases, the effective nuclear charge (Zeff) decreases. Orbitals in Many Electron Atoms Question In the chlorine atom ...

  • 17 Pages


    Ohio State, CHEM 121

    Excerpt: ... Chapter 7 Periodic Properties of the Elements R. Spinney 2009 Introduction Quantum Mechanics describes the electronic structure of atoms which correlates with the arrangement of the Periodic Table. This connection between electronic structure and chemical & physical properties allows us to make general statements about a number of properties of atom based to their position in the periodic table. A number of elements were discovered based on expected predictions of these missing elements! Effective Nuclear Charge As we have seen, in poly e- atoms, the subshells for any given n have different E This is due to the different e- - e- repulsions for ein different subshells. In addition we have subsets of e-; 1) core e-: 2) valence shell e-: Effective Nuclear Charge (contd) Primary interaction of e- & nucleus is due to charge: Coulombs Law: F = (kQeQn)/r2 However, the valence shell e- do not experience the full nuclear charge, they are shielded by the core e- Effective Nuclear Charge (contd) ...