1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 C H E M I S T R Y 1 1 · C H A P T E R 1 · E A S Y N O T E S What is the Periodic Table? S i m p l e A n a l o g y Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 1 of 15 4/7/2026, 6:32 PM 1 . 1 Pre-history 18th C. 1829 1864 1869 1913 Modern Periodic Law: 1 . 2 Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 2 of 15 4/7/2026, 6:32 PM T O T A L E L E M E N T S 118 elements, arranged in order of atomic number R O W S ( P E R I O D S ) 7 horizontal rows called C O L U M N S ( G R O U P S ) 18 vertical columns called S A M E G R O U P Same number of valence electrons → similar chemical properties P e r i o d v s G r o u p period group 1 . 3 M E T A L S lose electrons → positive ions left side N O N - M E T A L S gain electrons → negative ions right side Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 3 of 15 4/7/2026, 6:32 PM M E T A L L O I D S ( S E M I - M E T A L S ) both B Si Ge As Sb Te Po T h i n k o f i t l i k e t e m p e r a t u r e 1 . 4 4 blocks Groups 1 & 2 Groups 13–18 Groups 3–12 Lanthanides & Actinides S i m p l e w a y t o r e m e m b e r Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 4 of 15 4/7/2026, 6:32 PM 1 . 5 Group 1 ⁻ Group 2 ⁻ Groups 3–12 Group 16 Group 17 Group 18 W h y a r e N o b l e G a s e s u n r e a c t i v e ? 1 . 6 T W O S I M P L E R U L E S Period number = Shell number (n) → Group number = Number of valence electrons → Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 5 of 15 4/7/2026, 6:32 PM Example: → Magnesium (Mg)! A N O T H E R E X A M P L E — G R O U P 1 3 , P E R I O D 3 → Electronic config: 1s² 2s² 2p ⁶ 3s² 3p¹ → Aluminium (Al) 1 . 7 repeating pattern 1 . 7 . 1 A T O M I C R A D I U S D E F I N I T I O N picometers (pm) T R E N D S → Decreases → Increases A n a l o g y Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 6 of 15 4/7/2026, 6:32 PM → 1 . 7 . 2 I O N I C R A D I U S D E F I N I T I O N C A T I O N S ( + I O N S , L O S T E ⁻ ) Smaller than parent atom — lost a shell, nucleus pulls harder A N I O N S ( – I O N S , G A I N E D E ⁻ ) Larger than parent atom — more electrons = more repulsion = bigger cloud T R E N D S Decreases Increases 1 . 7 . 3 I O N I Z A T I O N E N E R G Y ( I E ) D E F I N I T I O N Na(g) → Na ⁺ (g) + e ⁻ · Δ H ᵢ₁ = 494 kJ/mol F A C T O R S T H A T A F F E C T I E Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 7 of 15 4/7/2026, 6:32 PM Nuclear charge ↑ → Atomic size ↑ → Half- � lled/fully- � lled orbitals → Shielding effect ↑ → Spin-pair repulsion → T R E N D S increases Decreases Special case: 1 . 7 . 4 E L E C T R O N A F F I N I T Y ( E A ) D E F I N I T I O N → negative Cl(g) + e ⁻ → Cl ⁻ (g) · Δ H°ea1 = –348.8 kJ/mol Second EA is positive: Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 8 of 15 4/7/2026, 6:32 PM F A C T O R S I N C R E A S I N G E A Smaller atom · Higher nuclear charge · Partially � lled orbitals F A C T O R S D E C R E A S I N G E A Larger atom · Lower nuclear charge · Half- � lled orbitals (N, P) T R E N D S more negative decreases W h y d o e s C l h a v e h i g h e r E A t h a n F ? 1 . 7 . 5 E L E C T R O N E G A T I V I T Y D E F I N I T I O N Pauling scale M I N I M U M ( 0 . 8 ) Alkali metals (Fr, Cs) — they want to give away electrons M A X I M U M ( 4 . 0 ) Fluorine (F) — strongest pull on shared electrons T R E N D S Increases Decreases A n a l o g y Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 9 of 15 4/7/2026, 6:32 PM 1 . 7 . 6 M E T A L L I C C H A R A C T E R D E F I N I T I O N T R E N D S → Decreases → Increases Cesium (Cs) 1 . 8 Na is more reactive than Mg W I T H W A T E R Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 10 of 15 4/7/2026, 6:32 PM 2Na(s) + 2H ₂ O(l) → 2NaOH(aq) + H ₂ (g) · Vigorous reaction Mg(s) + 2H ₂ O(l) → Mg(OH) ₂ (aq) + H ₂ (g) · Slow reaction Mg(s) + 2H ₂ O(g) → MgO(s) + 2H ₂ (g) · With steam, more vigorous W I T H O X Y G E N 2Na(s) + O ₂ (g) → 2Na ₂ O ₂ (s) · Golden yellow flame, kept under kerosene! 4Na(s) + O ₂ (g) → 2Na ₂ O(s) · Under limited O ₂ 2Mg(s) + O ₂ (g) → 2MgO(s) · Intense white flame W I T H C H L O R I N E 2Na(s) + Cl ₂ (g) → 2NaCl(s) · White solid, golden flame Mg(s) + Cl ₂ (g) → MgCl ₂ (s) · White solid 1 . 9 Key Trend: ionic → covalent Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 11 of 15 4/7/2026, 6:32 PM C L A S S I F I C A T I O N O F O X I D E S B A S I C O X I D E S metals → alkali (base) Na ₂ O(s) + H ₂ O(l) → 2NaOH(aq) CaO(s) + H ₂ O(l) → Ca(OH) ₂ (aq) A C I D I C O X I D E S non-metals → acid SO ₂ (g) + H ₂ O(l) → H ₂ SO ₃ (aq) P ₂ O ₃ (s) + H ₂ O(l) → H ₃ PO ₃ (aq) A M P H O T E R I C O X I D E S both ₂ ₃ Al ₂ O ₃ (s) + 6HCl(aq) → 2AlCl ₃ (s) + 3H ₂ O(l) [reacts with acid] Al ₂ O ₃ (s) + 2NaOH(aq) → 2NaAlO ₂ (s) + H ₂ O(l) [reacts with base] C L A S S I F I C A T I O N O F C H L O R I D E S Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 12 of 15 4/7/2026, 6:32 PM N E U T R A L C H L O R I D E S NaCl, MgCl ₂ — dissolve in water without reacting. pH ≈ 7. Ions simply hydrate. A C I D I C C H L O R I D E S AlCl ₃ , SiCl ₄ , PCl ₃ — react with water (hydrolysis) → produce HCl. pH < 7. AlCl ₃ (s) + 3H ₂ O(l) → Al(OH) ₃ (s) + 3HCl(aq) SiCl ₄ (l) + 2H ₂ O(l) → SiO ₂ (s) + 4HCl(aq) 1 . 1 0 W H A T I S O X I D A T I O N N U M B E R ? E E EL L LE E EM M ME E EN N NT T T O O OX X XI I ID D DE E E O O OX X XI I ID D DA A AT T TI I IO O ON N N # # # C C CH H HL L LO O OR R RI I ID D DE E E O O OX X XI I ID D DA A AT T TI I IO O ON N N # # # ₂ ₂ ₂ ₃ ₃ ₂ ₄ ₄ ₁₀ ₄ ₆ ₅ ₃ ₃ ₂ ₂ Why do P and S have variable oxidation states? ₂ → Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 13 of 15 4/7/2026, 6:32 PM ₃ → A C R O S S A P E R I O D ( L E F T → R I G H T ) Decreases Increases More negative Increases Decreases Increases D O W N A G R O U P ( T O P → B O T T O M ) Increases Decreases Decreases Decreases Increases Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 14 of 15 4/7/2026, 6:32 PM Chapter 1 – Periodic Table & Periodic Properties file:///C:/Users/Classic/Downloads/Chemistry_Ch1_Notes.html#s1 15 of 15 4/7/2026, 6:32 PM