CHEMSHEETS PERIODICITY www chemsheets co uk AS 1055

CHEMSHEETS PERIODICITY © www. chemsheets. co. uk AS 1055 3 -July-2015

s block p block d block The orbitals that the highest energy electrons are in © www. chemsheets. co. uk AS 1055 3 -July-2015

Calcium 20 e- 1 s 2 2 p 6 3 s 2 3 p 6 4 s 2 s block p block Ca d block The orbitals that the highest energy electrons are in © www. chemsheets. co. uk AS 1055 3 -July-2015

Iron 26 e- 1 s 2 2 p 6 3 s 2 3 p 6 4 s 2 3 d 6 s block d block p block Fe d block The orbitals that the highest energy electrons are in © www. chemsheets. co. uk AS 1055 3 -July-2015

Chlorine 17 e- 1 s 2 2 p 5 p block s block p block Cl d block The orbitals that the highest energy electrons are in © www. chemsheets. co. uk AS 1055 3 -July-2015

Helium 2 e- 1 s 2 s block He s block p block d block The orbitals that the highest energy electrons are in © www. chemsheets. co. uk AS 1055 3 -July-2015

ATOMIC RADIUS From: http: //2012 books. lardbucket. org/books/beginning-chemistry/s 12 -05 -periodic-trends. html

ATOMIC RADIUS © www. chemsheets. co. uk AS 1055 3 -July-2015

ATOMIC RADIUS Across a period: • outer electrons are in same shell • more protons in nucleus • same amount of shielding • so stronger attraction between nucleus and outer shell electrons • so outer shell electrons pulled closer to nucleus Na Mg Al Si P S © www. chemsheets. co. uk Cl AS 1055 3 -July-2015

1 st IONISATION ENERGY © www. chemsheets. co. uk AS 1055 3 -July-2015

1 st IONISATION ENERGY General trend across period • more protons • atoms get smaller • therefore stronger attraction from nucleus to electron in outer shell © www. chemsheets. co. uk AS 1055 3 -July-2015

1 st IONISATION ENERGY Group 2 → 3 • electron lost from: Group 3 = p orbital Group 2 = s orbital • p orbital is higher energy than s orbital, so easier to lose electron. © www. chemsheets. co. uk AS 1055 3 -July-2015

1 st IONISATION ENERGY Group 5 → 6 • Group 6 element loses electron from orbital with 2 electrons (p 4 ��� ). • Group 5 element loses electron from orbital with 1 electron (p 3 ��� ). • Extra electron-electron repulsions make it easier to lose electron from p 4 than p 3. © www. chemsheets. co. uk AS 1055 3 -July-2015

ELECTRONEGATIVITY H He 2. 1 Li Be B C N O F 1. 0 1. 5 2. 0 2. 5 3. 0 3. 5 4. 0 Na Mg Al Si P S Cl 0. 9 1. 2 1. 5 1. 8 2. 1 2. 5 3. 0 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br 0. 8 1. 0 1. 3 1. 5 1. 6 1. 5 1. 8 1. 9 1. 6 1. 8 2. 0 2. 4 2. 8 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I 0. 8 1. 0 1. 2 1. 4 1. 6 1. 8 1. 9 2. 2 1. 9 1. 7 1. 8 1. 9 2. 1 2. 5 Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At 0. 7 0. 9 1. 1 1. 3 1. 5 1. 7 1. 9 2. 2 2. 4 1. 9 1. 8 1. 9 2. 0 2. 2 Ne Ar Kr Xe Rn Power of an atom to attract the 2 electrons in a covalent bond

ELECTRONEGATIVITY Power of an atom to attract the 2 electrons in a covalent bond © www. chemsheets. co. uk AS 1055 3 -July-2015

ELECTRONEGATIVITY Power of an atom to attract the 2 electrons in a covalent bond Across a period: • more protons in nucleus • smaller atomic radius • so stronger attraction between nucleus and 2 electrons in covalent bond © www. chemsheets. co. uk AS 1055 3 -July-2015

MELTING & BOILING POINTS © www. chemsheets. co. uk AS 1055 3 -July-2015

MELTING & BOILING POINTS Na metallic Mg metallic Al metallic Si giant covalent P 4 simple molecular S 8 simple molecular Cl 2 simple molecular Ar monatomic • Strong attraction between metal ions and delocalised electrons • Al > Mg > Na as ü higher charge ü more delocalised electrons ü smaller ions © www. chemsheets. co. uk AS 1055 3 -July-2015

+ e-+ + e- +ee+ - + ee- ee+ + e+ e-+ e- e 2+ 2+ e e e e 2+ 2+ 2+ e e ee e 2+ 2+ Sodium (Na) Mpt 98ºC Magnesium (Mg) Mpt 650ºC - - ---- - - -

MELTING & BOILING POINTS Na metallic Mg metallic Al metallic Si giant covalent P 4 simple molecular S 8 simple molecular Cl 2 simple molecular Ar monatomic • Strong attraction between metal ions and delocalised electrons • Al > Mg > Na as ü higher charge ü more delocalised electrons ü smaller ions • Have to break many strong covalent bonds • Weak van der Waals’ forces between molecules • S 8 > P 4 > Cl 2 (bigger molecules, more electrons, more vd. W) • Very weak van der Waals’ forces between atoms © www. chemsheets. co. uk AS 1055 3 -July-2015