CONTENTS XX111 



597. Periodic system of the elements 485 



598. Atomic numbers 485 



599. Periodic system and the radioactive isotopes 486 



600. Atomic structure 487 



601. Electron configurations in normal atom 488 



602. Effective atomic radii 491 



Atomic Structure 



603. (a) Electrons, protons, Rutherford atom 492 



(b) Bohr atom, relativistic considerations 494 



(c) Hydrogen orbits, inner quantum numbers 495 



(d) The spinning electron, summary 496 



604. Energy of binding of an electron — neutral atoms 497 



605. singly ionized atoms 498 



606. First ionization potentials of the elements 499 



607. Second " " " " " 500 



608. Radiation units 501 



609. Spectrum ranges of various radiations 501 



610. The mechanical effects of radiation 501 



Atomic Spectrum Series Relations and Notations 



611. Normal series relations in atomic spectra 502 



612. Inner quantum numbers 503 



613. Spectroscopic notation 504 



614. Comparison series letters and azimuthal and Bohr's quantum 

 numbers 5°5 



615. Comparison of notations 506 



616. Ultimate spectrum lines, raies ultimes 507 



617. Persistent lines, arc spectra 509 



618. " " spark " 510 



619. Resonance lines 5 11 



620. Electron impacts in gases [producing ionization] 511 



621. Average life for various quantum states of excited atoms 511 



622. Molecular constants of diatomic molecules, [description] 512 



623. " " " " " [table] 513 



624. Various atomic and spectrum functions 515 



Radioactivity 



625. Introduction. The uranium family 516 



626. Ionium-radium family $ij 



627. Actinium family 518 



