CHEM 1110 1st Edition Lecture 24 Outline of Last Lecture I. Electron ConfigurationsOutline of Current Lecture I. Development of the Periodic Table II. Size of Atoms and Ions III. Effective Nuclear Charge Current LectureI. Development of the Periodic Table A. Mendeleev 18691. Mendeleev’s periodic table was based on experimental behavior and repeating patternsB. Evolution of the Periodic Table 1. John Newland a. Arranged elements by atomic mass2. Dmitri Mendeleeva. Organized table of 66 elements based on increasing atomic mass and chemical/physical properties 3. Henry Moseleya. Developed concept of atomic numbers and resolved inconsistencies in atomic mass arrangement – predicted new elements These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.b. Predicted several unknown elements c. Derived from experimental datai. Not based on theory II. Size of Atoms and Ions A. Atomic Radius1. Bonding radius- ½ of a molecular bond a. Radius= .5 d2. Non-bonding or van der Waals radius – ½ of closest interatomic distance a. d= 2x radius B. Atomic radius down a group 1. Atomic radius increases down a group2. Makes sense: change in size is due to the fact that there are more electrons 3. Reflected in change in principle quantum #4. Go across a row, radius decreases C. Explaining the trend in atomic size1. Size depends on the balance between the:a. Attractions of the protons and electrons b. Repulsions between the electrons in the atoms 2. the number of core electrons influence the balance between attraction and repulsion D. Coulomb’s Law1. Models both attractions between the protons and electrons, and repulsions between the electrons III. Effective Nuclear Charge A. Effective nuclear charge: the net positive charge experienced by an electron in a many-electron atomB. In many-electron atoms, other electrons, especially inner electrons (also called core electrons), screen the charge felt by the outer valence
View Full Document
Unlocking...