CH110 Lecture Notes - Lecture 17: Chalcogen, Transition Metal, Metal
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Main group non-metal ions: group 16 and 17. The atoms of group 16 and 17 are the most reactive toward gaining an electron. Gaining one e (group 17) or two e (group 16) electrons the elements achieve a noble gas electron configuration. (group 17) br ([ar]3d104s24p5) + e br ([kr]) (group 16) se ([ar]3d104s24p4) + 2e se2 ([kr]) Group 16 elements tend to form 2 ions while group 17 tend to form 1 ions. The transition metal elements only form cations (they lose electrons) Many elements are capable of forming one or more cations +1, +2, +3, etc. (e. g. fe2+, fe3+, cr2+, cr3+, mn2+, mn3+, mn4+) When we fill the d block elements with electrons, we fill the ns orbital first then the (n 1)d orbitals (e. g. 4s first then the 3d) Recall from chapter 8: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p
