CHEM 111 Lecture Notes - Lecture 22: Metal, Noble Gas, Electron Configuration
20 Dec 2016
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Electron fill orbitals from lowest to highest energy. Electron configuration is the total electrons from lowest to highest shell. Larger n orbital energy increases (same l: 4s orbital higher in energy than 3s orbital. Larger l orbital energy increases: in n = 2 shell, 3s < 3p < 3d. N increases subshells more closely spaced, overlapping: 4f orbital higher in energy than 5s. Ex: nitrogen: it has 7 electrons, electron configuration is 1s22s22p3. D-block: [noble gas] (n-1)dxns2: examples, n=4 mn [ar] 3d54s2, n=5 ru [kr] 4d65s2, n=6 ta [xe] 4f145d36s2. Electron configurations written by shell even though electrons fill by the periodic table: for ni, the last electron is to fill 3d8. Electron configuration by filling order: [1s22s22p63s23p6]4s23d8] 4s2 3d8. Electron configuration by shell: [1s22s22p63s23p6] 3d8 4s2. The promotion of a 4s electron to a 3d orbital: example: cr: [ar] 3d5 4s1. Half-filled or full orbital is more stable than a partially filled orbital.
