[{"data":1,"prerenderedAt":147},["ShallowReactive",2],{"cheatsheet-atomic-structure-and-isotopes":3},{"sheet":4},{"sheetSlug":5,"topicSlugs":6,"primaryTopic":7,"title":8,"subtitle":9,"sections":10},"atomic-structure-and-isotopes",[5],3,"Atomic Structure & Isotopes","Subatomic particles, atomic and mass number, isotopes, average atomic mass, shells, and Lewis dots.",[11,28,36,60,68,81,99,112,125,134],{"heading":12,"kind":13,"items":14},"Subatomic particles","rules",[15,23],{"ref":16,"mode":19,"provenance":20,"text":21,"source_hash":22},{"type":17,"topic":7,"id":18,"field":17},"rule","ATM-R001","transform","original","Proton: +1, in the nucleus. Neutron: 0 charge, in the nucleus. Electron: −1, outside the nucleus.","914e8e76e14c15f4de1dd2d1dfa74e04d36de163bf3ee9d122b29042e57d2ad7",{"ref":24,"mode":19,"provenance":20,"text":26,"source_hash":27},{"type":17,"topic":7,"id":25,"field":17},"ATM-R002","Proton ≈ neutron ≈ 1 amu; electron ≈ 0.00055 amu (far lighter).","053bb826cc96fe448e33e848136d3ba59ed6594320d4f7538db512b59c82d5a3",{"heading":29,"kind":13,"items":30},"Neutral atom",[31],{"ref":32,"mode":19,"provenance":20,"text":34,"source_hash":35},{"type":17,"topic":7,"id":33,"field":17},"ATM-R003","In a neutral atom, electrons = protons. Nearly all the mass is in the nucleus.","fcf3bb4e00ffd26acb5859461e1f8b4db1680279ab7a6d9c7fafd124fa3d9079",{"heading":37,"kind":38,"items":39},"Counting particles","steps",[40,45,50,55],{"ref":41,"mode":19,"provenance":20,"text":43,"source_hash":44},{"type":17,"topic":7,"id":42,"field":17},"ATM-R004","Z (atomic number) = number of protons; it identifies the element.","8e8f517edeb87c85982e8d7101bb2d2c821baab7548de468958563c10cb0e973",{"ref":46,"mode":19,"provenance":20,"text":48,"source_hash":49},{"type":17,"topic":7,"id":47,"field":17},"ATM-R005","A (mass number) = protons + neutrons = Z + N.","8de958533f1737a2c0796c5bf1713225dc03e83e6d3fa660930ae37b0b89772c",{"ref":51,"mode":19,"provenance":20,"text":53,"source_hash":54},{"type":17,"topic":7,"id":52,"field":17},"ATM-R006","Neutrons: N = A − Z.","b3d9c6e6f5386491711d0385bd39fd51052b4cd076db4738348622e509647e05",{"ref":56,"mode":19,"provenance":20,"text":58,"source_hash":59},{"type":17,"topic":7,"id":57,"field":17},"ATM-R007","Ion electrons = Z − charge (positive: lost electrons; negative: gained electrons).","4cb0f5827043573a2d39567d2f528ba414f325ede6f26e362dd241f0bafbcc8a",{"heading":61,"kind":13,"items":62},"Isotopes",[63],{"ref":64,"mode":19,"provenance":20,"text":66,"source_hash":67},{"type":17,"topic":7,"id":65,"field":17},"ATM-R008","Isotopes: same element (same protons), different neutron count and mass number.","ad6f9c3712c09c49e0b11d42fd63a0a124facb5cccc31712b8c8992bed9d870b",{"heading":69,"kind":13,"items":70},"Isotope notation",[71,76],{"ref":72,"mode":19,"provenance":20,"text":74,"source_hash":75},{"type":17,"topic":7,"id":73,"field":17},"ATM-R009","Symbol notation: mass number A as left superscript, atomic number Z as left subscript (e.g. ¹⁴₆C).","3597a864e4760c9d3f9647a4a18e203f16e63a01fc54c70d146288d5612c9f41",{"ref":77,"mode":19,"provenance":20,"text":79,"source_hash":80},{"type":17,"topic":7,"id":78,"field":17},"ATM-R010","Name notation: element name + hyphen + mass number (carbon-14, uranium-235).","ae457a041ec593749a94677e241e9207f82fd0281e393d7a162671233ca3be4d",{"heading":82,"kind":38,"items":83},"Average atomic mass",[84,89,94],{"ref":85,"mode":19,"provenance":20,"text":87,"source_hash":88},{"type":17,"topic":7,"id":86,"field":17},"ATM-R011","Weighted average = Σ (isotopic mass × fractional abundance).","5fc098fcfb2e140436981991794cb3bbcc70bbfce3b58a6f55d7bdb13a71519f",{"ref":90,"mode":19,"provenance":20,"text":92,"source_hash":93},{"type":17,"topic":7,"id":91,"field":17},"ATM-R012","Convert % abundance to decimal first; fractional abundances sum to 1.00.","701e73e5b91e4eeb8c4924ad4b6904d4f7664c58a00f1cbaa746a1a9ff26b401",{"ref":95,"mode":19,"provenance":20,"text":97,"source_hash":98},{"type":17,"topic":7,"id":96,"field":17},"ATM-R013","The more abundant isotope pulls the average toward its mass; that is why atomic masses are not whole numbers.","0ac33a54fd267d2943c0994fe3d4e24f666bbfd227904deb4b85670b04da5155",{"heading":100,"kind":13,"items":101},"Electron shells (first 20 elements)",[102,107],{"ref":103,"mode":19,"provenance":20,"text":105,"source_hash":106},{"type":17,"topic":7,"id":104,"field":17},"ATM-R015","Introductory fill pattern through calcium: 2, 8, 8, then up to 2 in shell 4 (not the full physical capacities).","6c755975252f28bb2785d340554e40b6749abd3f1b457c4334d3256b21e7d1cf",{"ref":108,"mode":19,"provenance":20,"text":110,"source_hash":111},{"type":17,"topic":7,"id":109,"field":17},"ATM-R016","Valence electrons (main group) = electrons in the outermost occupied shell.","d69a96d11d2d4d580e479708de048b648b7840c9a3763d281eabc7627b2baf80",{"heading":113,"kind":13,"items":114},"Lewis dot symbols",[115,120],{"ref":116,"mode":19,"provenance":20,"text":118,"source_hash":119},{"type":17,"topic":7,"id":117,"field":17},"ATM-R017","Element symbol surrounded by one dot per valence electron.","e9d06da8aa91ae27df6fce91a152dfb08868d8fdad6550a75b7cdd16349cc1a2",{"ref":121,"mode":19,"provenance":20,"text":123,"source_hash":124},{"type":17,"topic":7,"id":122,"field":17},"ATM-R018","One dot on each side before pairing a second on any side. He is drawn with 2 (its first shell is full).","d5efe879ce344b35a739f1ca735879e6a10e8aede219f1847370ab9b6dfeca81",{"heading":126,"kind":127,"items":128},"Common ion charges","data",[129],{"ref":130,"mode":19,"provenance":20,"text":132,"source_hash":133},{"type":17,"topic":7,"id":131,"field":17},"ATM-R019","Group 1 → +1 · Group 2 → +2 · Al → +3 · Group 16 → −2 · Group 17 → −1 · N, P → −3. Introductory patterns, not universal.","ebd363d0e01817197e5b2278b7adbe310787af348349f99e12c0a202ccb1b868",{"heading":135,"kind":13,"items":136},"Ionic formulas & naming",[137,142],{"ref":138,"mode":19,"provenance":20,"text":140,"source_hash":141},{"type":17,"topic":7,"id":139,"field":17},"ATM-R020","Balance charge with the cross-over rule (each ion's charge magnitude becomes the other's subscript), then reduce to the smallest whole-number ratio.","ccd5fe49c1c9001e70015f41c35e28273fac932cf75f81e85bf4b5d81b668a5c",{"ref":143,"mode":19,"provenance":20,"text":145,"source_hash":146},{"type":17,"topic":7,"id":144,"field":17},"ATM-R021","Binary ionic name: metal + nonmetal root + -ide. Na⁺ + Cl⁻ → NaCl; Mg²⁺ + O²⁻ → MgO; Li⁺ + S²⁻ → Li₂S; Al³⁺ + N³⁻ → AlN.","70630a1b44826727afba23de2bb0e7c1130011ff9e4e3d797b1c1fa9927bdb50",1787246033014]