Atomic Structure Reference Sheet
Chemistry Survival Guide Investigation 1B Review
Atomic Structure & Electrons Reference Sheet
Name: ______________________
Period: _____ Date: ____________
1
Anatomy of an Atom & Bohr Models
Essential Formulas
Atomic # (\(Z\)): = # of Protons
Neutral Atom: Protons = Electrons
Mass Number: \(P + N\)
# Neutrons: Mass − Protons
Ring Capacities:
R1: 2
R2: 8
R3: 8
Sodium (\(\text{Na}\)) • Mass 23 11 P 12 N Valence (1)
Period: 3 (3 rings) | Grp: 1
1 VE → Unstable
Sulfur (\(\text{S}\)) • Mass 32 16 P 16 N
Period: 3 | Group: 16
6 VE → Needs 2 more to be Stable!
2
Flame Lab: How Atoms Make Light & Spectra
ELECTRON ENERGY TRANSITIONS (FLAME TEST)
Excited State (High E) Ground State (Low E) 1. Normal 🔥 Flame Energy → JUMP 2. Excited 3. FALLS DOWN Photon Emitted (Light!)
Atomic Emission Spectra Element Fingerprint
Each element emits a unique pattern of wavelengths (like DNA fingerprints).
400nm (Violet) Hydrogen Line Spectrum 700nm (Red)
⚡ Key Fact: Light is ONLY emitted when electrons FALL from excited back to ground state!
3
Modern Atomic Theory & 3D Orbital Shapes
Current Model: Quantum Mechanical Model (Probability Cloud)
RULE: Each single orbital holds MAX 2 electrons!
| Sublevel | Shape Diagram | Shape Name | # of Orbitals | Max Electrons | Orbital Boxes |
|---|
| s | | Sphere (1 orientation) | 1 | 2 \(e^-\) | [ ] |
| p | | Dumbbell / Peanut (x, y, z) | 3 | 6 \(e^-\) | [ ][ ][ ] |
| d | | Four-leaf clover (5 shapes) | 5 | 10 \(e^-\) | [ ][ ][ ][ ][ ] |
| f | | Complex / Flower (7 shapes) | 7 | 14 \(e^-\) | 7 boxes |
1s 2s 2p 3s
Nested Cloud Capacity (Question 13):
If \(1s, 2s, 2p,\) and \(3s\) are all completely full:
2(1s) + 2(2s) + 6(2p) + 2(3s) = 12 total electrons!
Page 1: Atomic Structure, Bohr Models, & Orbital Shapes • Turn over for Periodic Table & Electron Configurations →
Periodic Table Blocks & Electron Configurations
Decoding groups, periods, filling order, and noble gas shorthand
Page 2 Cheat Sheet
4
Periodic Table Block Map, Groups & Periods
1 2 3 4 5-11 12 13 14 15 16 17 18 1 VE 2 VE 3 4 5 6 7 8 VE P1 P2 P3 P4 P5 P6 P7 s-block (1s – 7s) d-block Transition Metals • Energy level is (Row − 1): 3d, 4d, 5d, 6d p-block (2p – 7p) He (1s) f-block (4f & 5f) Lanthanides & Actinides • Energy level is (Row − 2) HOW TO READ THE PERIODIC TABLE: Periods = Horizontal Rows (1 – 7) → Tells you highest principal energy level (\(n\)) & # of rings! Groups = Vertical Columns (1 – 18) → Same group = same valence electrons & similar reactivity! Valence Electron Shortcut (Main Groups): Grp 1 = 1 VE • Grp 2 = 2 VE • Grp 13 = 3 VE • Grp 14 = 4 VE Grp 15 = 5 VE • Grp 16 = 6 VE • Grp 17 = 7 VE • Grp 18 = 8 VE (He=2) ✓ Stable atoms have 8 VE (Full Octet)!
5
Electron Configurations: Step-by-Step
Aufbau Filling Sequence: 1s → 2s → 2p → 3s → 3p → 4s → 3d → 4p → 5s → 4d → 5p
Longhand Configuration Add exponents
- Find total electrons (neutral atom: \(P = E\)).
- Fill sublevels in Aufbau order: \(s^2, p^6, d^{10}, f^{14}\).
- Sum of superscripts MUST equal total electrons!
Phosphorus (\(\text{P}\), 15 \(e^-\)):
1s² 2s² 2p&sup6; 3s² 3p³ Check: 2+2+6+2+3 = 15 ✓
Germanium (\(\text{Ge}\), 32 \(e^-\)):
1s² 2s² 2p&sup6; 3s² 3p&sup6; 4s² 3d¹&sup0; 4p²
Noble Gas Shorthand Time Saver!
- Go UP one row & all the way RIGHT → Noble Gas in \([\dots]\).
- Continue writing from the start of your element's row.
Vanadium (\(\text{V}\), 23 \(e^-\)):
[Ar] 4s² 3d³ ([Ar] = 18 \(e^-\))
Tin (\(\text{Sn}\), 50 \(e^-\)):
[Kr] 5s² 4d¹&sup0; 5p²
Valence = outer shell (\(n=5\)): \(5s^2 + 5p^2 = \mathbf{4\text{ VE}}\)
6
Orbital Diagrams (Arrows) & Lewis Structures (Dots)
Arrow Rules (Pauli & Hund) Bus Seat Rule!
Pauli: Opposite spins in each box: ↑↓
Hund: 1 up-arrow in each box before pairing!
Nitrogen (\(\text{N}\), 7 \(e^-\)): \(1s^2 2s^2 2p^3\) 3 single arrows in 2p
↑↓
1s
↑↓
2s
↑
↑
↑
2p (Hund's Rule)
Iron (\(\text{Fe}\), 26 \(e^-\)): Ends with \(4s^2 3d^6\) 4s fills before 3d!
↑↓
4s
↑↓
↑
↑
↑
↑
3d (6 electrons)
Lewis Dot Structures Valence Only
Place 1 dot on each side (top, right, bottom, left) before pairing!
Be (2 VE) Be Unstable
O (6 VE) O Unstable
Ne (8 VE) Ne STABLE!
Octet Rule: Full ring of 8 electrons = completely stable!
Investigation 1B Chemistry Reference Cheat Sheet • Designed for High School Co-Taught Chemistry
