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Physical Properties

Across Period

Down Group

파일

Effective nuclear charge (Zeff) Nuclear charge experienced by the valence e-s Number of protons - number of non-valence e-s due to shielding

↑

Same

Atomic radius Half the distance b/w nuclei of two neighbouring atoms (distance b/w nucleus and outermost e-)

↓ ˙.˙ effective nuclear charge ↑ Electrostatic ↑ Distance ↓ “Atomic shrinkage” “Results in valence shell being pulled more strongly to the nucleus”

↑ ˙.˙ no. e- shells ↑ Distance ↑ Electrostatic ↓ “Atomic/ionic expansion”

Ionic radius Half the distance b/w nuclei of two neighbouring ions (distance b/w nucleus and outermost e-) *No value for Group 18 Ionic vs atomic radii (same nuclear charge & different no. of valence e-s) *For group 1 to 14, ionic < atomic radius ˙.˙ of loss of an e- shell & same no. of protons pulling lower no. of e-s *For group 14 to 17, ionic > atomic radius ˙.˙ of more no. of e- and e--e- repulsion caused expansion/same no. of protons pulling higher no. of e-s (e.g. Cl vs Cl-)

(different nuclear charge & same no. of valence e-s) ↓ from group 1 to 14 ˙.˙ Nuclear charge ↑ Electrostatic ↑ Distance ↓ “Ionic shrinkage” Jump ˙.˙ a new e- shell is introduced ↓ from group 4 to 7 ˙.˙ Nuclear charge ↑ Electrostatic ↑ Distance ↓ “Ionic shrinkage” *Original vs X large doughnut & 8 different weighted consumer analogy*

Ionization energy Energy required to remove 1 mole of e-s from 1 mole of gaseous atoms (kJ mol-1) X(g) → X+(g)+ e– “Endothermic as bond broken between removed e- and nucleus”

*Staircase analogy* Overall ↑ ˙.˙ effective nuclear charge ↑Atomic radius ↓ Electrostatic ↑ Very high value for Group 18 ˙.˙ noble gases do not want to lose full octet

↓ ˙.˙ no. e- shells ↑ Distance ↑ Electrostatic ↓ “Easier to remove e-”

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Electron Affinity Energy change when 1 mole of electrons is added to 1 mole of gaseous atoms X(g) + e– → X–(g) *No value for Group 18 (do not form -ve ion) “Exothermic as bond formed between new e- and nucleus”

Overall ↑ (more exothermic) ˙.˙ effective nuclear charge ↑ Electrostatic ↑ Energy released ↑ Jump b/w 1 & 2 (endothermic) ˙.˙ added e- is placed at p orbital that is further away from nucleus (shielding) Attraction b/w e- and nucleus is weaker Less energy released/exothermic (actually endothermic) Jump b/w 14 & 15 ˙.˙ e- added to an already half-filled orbital new e- is pushed further away from nucleus due to e- - e- repulsion Attraction b/w e- and nucleus is weaker Less energy released/exothermic *N/A for Group 18 *2nd e- affinity is endothermic ˙.˙ energetically unfavourable to remove e- from -ve ion

↓ ˙.˙ no. e- shells ↑ Distance ↑ Electrostatic ↓ “Difficult to gain e-”

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Electronegativity 1. Ability of an atom to pull a shared pair of e-s to its nucleus 2. Effective nuclear charge experienced by a shared pair of e-s

↑ ˙.˙ effective nuclear charge ↑ Electrostatic ↑

↓ ˙.˙ no. e- shells ↑ Distance ↑ Electrostatic ↓

Metallic and non-metallic behaviour

↓ ˙.˙ I.E. ↑ .˙. Less likely to be oxidised (ionised)

↓ ˙.˙ Ionic radius ↓ More easily oxidised (ionised)

Repeating Tags

distance b/w nucleus and valence e- electrostatic attraction b/w nucleus and valence e-