Periodic Relationships Among the Elements Chapter 8 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

8.1 When the Elements Were Discovered

8.2 ns 1 ns 2 ns 2 np 1 ns 2 np 2 ns 2 np 3 ns 2 np 4 ns 2 np 5 ns 2 np 6 d1d1 d5d5 d 10 4f 5f Ground State Electron Configurations of the Elements

8.2 Classification of the Elements

Electron Configurations of Cations and Anions Na [Ne]3s 1 Na + [Ne] Ca [Ar]4s 2 Ca 2+ [Ar] Al [Ne]3s 2 3p 1 Al 3+ [Ne] Atoms lose electrons so that cation has a ____________ _______________ electron configuration H 1s 1 H - 1s 2 or [He] F 1s 2 2s 2 2p 5 F - 1s 2 2s 2 2p 6 or [Ne] O 1s 2 2s 2 2p 4 O 2- 1s 2 2s 2 2p 6 or [Ne] N 1s 2 2s 2 2p 3 N 3- 1s 2 2s 2 2p 6 or [Ne] Atoms gain electrons so that anion has a ___________________ electron configuration. Of Representative Elements 8.2

Cations and Anions Of Representative Elements 8.2

Na + : [Ne]Al 3+ : [Ne]F - : 1s 2 2s 2 2p 6 or [Ne] O 2- : 1s 2 2s 2 2p 6 or [Ne]N 3- : 1s 2 2s 2 2p 6 or [Ne] Na +, Al 3+, F -, O 2-, and N 3- are all _______________ with Ne What neutral atom is isoelectronic with H - ? H - : 1s 2 same electron configuration as _____ 8.2

Electron Configurations of Cations of Transition Metals 8.2 When a cation is formed from an atom of a transition metal, electrons are always removed first from the ns orbital and then from the (n – 1)d orbitals. Fe: [Ar]4s 2 3d 6 Fe 2+ : [Ar]4s 0 3d 6 or [Ar]3d 6 Fe 3+ : [Ar]4s 0 3d 5 or [Ar]3d 5 Mn: [Ar]4s 2 3d 5 Mn 2+ : [Ar]4s 0 3d 5 or [Ar]3d 5

__________ __________ __________ (Z eff ) is the “positive charge” felt by an electron. Na Mg Al Si Z eff Core Z Radius (pm) Z eff = Z -  0 <  < Z (  = __________ ___________) Z eff  Z – number of inner or core electrons 8.3

Effective Nuclear Charge (Z eff ) 8.3 increasing Z eff

8.3

Atomic Radii 8.3

Comparison of Atomic Radii with Ionic Radii

Cation is always ___________ than atom from which it is formed. Anion is always ___________ than atom from which it is formed. 8.3

The Radii (in pm) of Ions of Familiar Elements

Chemistry in Action: The 3 rd Liquid Element? Liquid? 113 elements, 2 are liquids at 25 0 C – Br 2 and Hg 223 Fr, t 1/2 = 21 minutes

___________ __________ is the minimum energy (kJ/mol) required to remove an electron from a gaseous atom in its ground state. I 1 + X (g) X + (g) + e - I 2 + X + (g) X 2 + (g) + e - I 3 + X 2+ (g) X 3 + (g) + e - I 1 first ionization energy I 2 second ionization energy I 3 third ionization energy 8.4 I 1 < I 2 < I 3

8.4

Filled n=1 shell Filled n=2 shell Filled n=3 shell Filled n=4 shell Filled n=5 shell 8.4 Variation of the First Ionization Energy with Atomic Number

General Trend in First Ionization Energies 8.4 Increasing First Ionization Energy

____________ _____________ is the negative of the energy change that occurs when an electron is accepted by an atom in the gaseous state to form an anion. X (g) + e - X - (g) 8.5 F (g) + e - X - (g) O (g) + e - O - (g)  H = -328 kJ/mol EA = +328 kJ/mol  H = -141 kJ/mol EA = +141 kJ/mol

8.5

Variation of Electron Affinity With Atomic Number (H – Ba)

8.6

Group 1A Elements (ns 1, n  2) M M e - 2M (s) + 2H 2 O (l) 2MOH (aq) + H 2(g) 4M (s) + O 2(g) 2M 2 O (s) Increasing reactivity 8.6

Group 1A Elements (ns 1, n  2) 8.6

Group 2A Elements (ns 2, n  2) M M e - Be (s) + 2H 2 O (l) No Reaction Increasing reactivity 8.6 Mg (s) + 2H 2 O (g) Mg(OH) 2(aq) + H 2(g) M (s) + 2H 2 O (l) M(OH) 2(aq) + H 2(g) M = Ca, Sr, or Ba

Group 2A Elements (ns 2, n  2) 8.6

Group 3A Elements (ns 2 np 1, n  2) 8.6 4Al (s) + 3O 2(g) 2Al 2 O 3(s) 2Al (s) + 6H + (aq) 2Al 3+ (aq) + 3H 2(g)

Group 3A Elements (ns 2 np 1, n  2) 8.6

Group 4A Elements (ns 2 np 2, n  2) 8.6 Sn (s) + 2H + (aq) Sn 2+ (aq) + H 2 (g) Pb (s) + 2H + (aq) Pb 2+ (aq) + H 2 (g)

Group 4A Elements (ns 2 np 2, n  2) 8.6

Group 5A Elements (ns 2 np 3, n  2) 8.6 N 2 O 5(s) + H 2 O (l) 2HNO 3(aq) P 4 O 10(s) + 6H 2 O (l) 4H 3 PO 4(aq)

Group 5A Elements (ns 2 np 3, n  2) 8.6

Group 6A Elements (ns 2 np 4, n  2) 8.6 SO 3(g) + H 2 O (l) H 2 SO 4(aq)

Group 6A Elements (ns 2 np 4, n  2) 8.6

Group 7A Elements (ns 2 np 5, n  2) X + 1e - X - 1 X 2(g) + H 2(g) 2HX (g) Increasing reactivity 8.6

Group 7A Elements (ns 2 np 5, n  2) 8.6

Group 8A Elements (ns 2 np 6, n  2) 8.6 Completely filled ns and np subshells. Highest ionization energy of all elements. No tendency to accept extra electrons.

Properties of Oxides Across a Period basicacidic 8.6

Chemistry in Action: Discovery of the Noble Gases Sir William Ramsay