CHEM 6A Lecture Notes - Lecture 19: Ionic Radius, Sign Convention, Covalent Bond

• School: UCSD
• Department: Chemistry and Biochemistry
• Course: CHEM 6A
• Professor: Tin Yiu Lam

Document Summary

When filled, energy of the orbitals: 3d < 4s. Different dominating factor when considering across a period or down a group. Electron-electron repulsion causes shielding effect, meaning most electrons do not feel. Effective nuclear charge, zeff the full charge of the nucleus (zeff z) We are interested in zeff experienced by the valence electrons. Across a period zeff increases as each addition electron to the same subshell does not increase shielding significantly to counteract attraction from each additional proton. Electrons aren"t affected as much by the nucleus charge since the repulsion of other electrons shield the nucleus. Distance between atoms of covalent bonds smaller than atoms of metallic bonds. Electron-electron repulsion in d orbitals opposes increasing effective nuclear charge. Excess positive charge(s) of nucleus increase attraction to electrons. Electron-electron repulsion increases in same subshell (but same nuclear charge) General trends and rationales for atomic size still apply. Atoms or ions with the same number of electrons.