Grade 11 Chemistry - the Periodic Table Notes
By stressly
Oct 14, 2012
796 Words
Chapter 11 - The Periodic Table
11-1 Organizing by Properties
Dmitri Mendeleev (1834-1907) russian, published his element classification in 1869 - increasing molar mass - matching similar properties Mendeleev's periodic table included gaps - yet to be discovered - predicted the properties of missing elements repetition in properties of the elements was a fundamental pattern in nature - periodicity of the elements modern periodic law: the properties of the elements recur periodically when the elemetns are arranged in increasing order by their atomic numbers
11-2 The Periodic Table Today
(Table 11-1 pg 307)
helium, neon and argon do not form hydrides or fluorides - can be grouped the ratio to H and ratio to F are in groups with sequence 1, 2, 3, 4, 3, 2, 1 elements with same ratios mean they react similarly to H and F periodic table: vertical groups/chemical families
groups 1, 2, 12, 14, 15, 16, 17 and 18 known as the representative elements elements in groups all react similarly to the same situations
group 1: alkali metals (excluding H) - these metals react with water to form an alkali/basic solution group 2: alkaline earth metals
group 17: halogens
group 18: noble gases - nonreactive under most conditions
group 3-12: transition metals - once believed that they behaved in a manner that is intermediate between the active metals and non metals
horizontal rows: periods
rare earth metals replaced with term inner transition metals or lanthanides series (57 to 71) actinide series (part of the inner trans. metals): elements 89 to 103
Patterns in Electrons Structure
11-3 The Periodic Table and Electron Configuration
Li: 1s2 2s1 / K: 1s2 2s2 2p6 3s2 3p6 4s1 / Ar: 1s2 2s2 2p6 3s2 3p6 / Kr 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 (electron configurations) electrons in the outermost s and p orbitals are referred to as valence electrons each group is characterized by a similar outermost energy lvl configuration, that's why they react similarly transition metals in period 4: 3d orbital being filled one at a time transition metals in period 5: 4d orbital being filled one at a time
11-4 Electron Configuration and Chemical Behaviour
Na+ ion and Ne atom are isoelectronic b/c they have the same electron configuration alkali metals: ion charge of 1+
alkaline metals: ion charge of 2+, isoelectronic with same element witb alkali metals halogens: ion charge of 1-, isoelectronic with the nearest noble gas metals lose electrons and form +ions / nonmetals gain (or share) and form - ions
Periodic Trends
11-5 Atomic and Ionic Radii
atomic radius: determine the distance between nuclei of metal atoms in a crystal / for elements in pure form as molecules, distance between nuclei for two atoms bonded together x ray diffraction technique
covalent radius: half of measurement described above
ionic radius: measure of the size of the electron probability volume for an ion
atomic radii decrease ® in a period
reason : as nuclear charge (protons in nucleus) increases, attraction is greater and atomic radius is smaller atomic/ionic radii increase ¯ in a group or family
reason 1: # of electrons increase, therefore more orbitals further away from nucleus reason 2: shielding effect - inner electrons shield the valence electrons from the attractive force from nucleus
- weakens the force between nucleus and valence electrons
the positive ion formed when an atom loses its valence electron is smaller than the neutral atom if neutral atom gains, electron, bigger. b/c increase neg charge results in greater mutual repulsion among the electrons - also reduces the attractive force of the nucleus
11-6 Ionization Energy
ionization energy: energy needed to remove an electron from a neutral gaseous atom
Element (g) + ionization energy ® Ion+ (g) + e-
determined in the 1920’s by bombarding gaseous element samples with high energy electrons
energy of bombarding electrons known precisely
when electrons gain enough kinetic energy, atoms start to ionize
first ionization energy - energy needed to eject the most weakly held electron to form pos ion low ionization energy: forms pos ion
high ionization energy: may form neg ions or no ions at all
IE1, IE2, IE3, IE4, IE5, is the energy needed to remove the outermost, next outermost, third, fourth and fifth outermost electrons from the atom, respectively (from valence to inner) IE increase ® in each period / alkali metal low, noble gas high
noble gases the smallest = greater nuclear charge = high energy to rid electron IE2 for Li and He differs even though they both have same electron configuration
reason: Li has nuclear charge of 3+ / He has nuclear charge of 2+
thus greater IE for Li
problems
2. a) x=1, y=3 b) x=3, y=1 or 3 c) x=2, y=4 or 2 d) x=3, y=2 3. a) SrS b)GaF3 c) BeTe d)ClI e) AsBr3
7. 3+, 3
11-1 Organizing by Properties
Dmitri Mendeleev (1834-1907) russian, published his element classification in 1869 - increasing molar mass - matching similar properties Mendeleev's periodic table included gaps - yet to be discovered - predicted the properties of missing elements repetition in properties of the elements was a fundamental pattern in nature - periodicity of the elements modern periodic law: the properties of the elements recur periodically when the elemetns are arranged in increasing order by their atomic numbers
11-2 The Periodic Table Today
(Table 11-1 pg 307)
helium, neon and argon do not form hydrides or fluorides - can be grouped the ratio to H and ratio to F are in groups with sequence 1, 2, 3, 4, 3, 2, 1 elements with same ratios mean they react similarly to H and F periodic table: vertical groups/chemical families
groups 1, 2, 12, 14, 15, 16, 17 and 18 known as the representative elements elements in groups all react similarly to the same situations
group 1: alkali metals (excluding H) - these metals react with water to form an alkali/basic solution group 2: alkaline earth metals
group 17: halogens
group 18: noble gases - nonreactive under most conditions
group 3-12: transition metals - once believed that they behaved in a manner that is intermediate between the active metals and non metals
horizontal rows: periods
rare earth metals replaced with term inner transition metals or lanthanides series (57 to 71) actinide series (part of the inner trans. metals): elements 89 to 103
Patterns in Electrons Structure
11-3 The Periodic Table and Electron Configuration
Li: 1s2 2s1 / K: 1s2 2s2 2p6 3s2 3p6 4s1 / Ar: 1s2 2s2 2p6 3s2 3p6 / Kr 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 (electron configurations) electrons in the outermost s and p orbitals are referred to as valence electrons each group is characterized by a similar outermost energy lvl configuration, that's why they react similarly transition metals in period 4: 3d orbital being filled one at a time transition metals in period 5: 4d orbital being filled one at a time
11-4 Electron Configuration and Chemical Behaviour
Na+ ion and Ne atom are isoelectronic b/c they have the same electron configuration alkali metals: ion charge of 1+
alkaline metals: ion charge of 2+, isoelectronic with same element witb alkali metals halogens: ion charge of 1-, isoelectronic with the nearest noble gas metals lose electrons and form +ions / nonmetals gain (or share) and form - ions
Periodic Trends
11-5 Atomic and Ionic Radii
atomic radius: determine the distance between nuclei of metal atoms in a crystal / for elements in pure form as molecules, distance between nuclei for two atoms bonded together x ray diffraction technique
covalent radius: half of measurement described above
ionic radius: measure of the size of the electron probability volume for an ion
atomic radii decrease ® in a period
reason : as nuclear charge (protons in nucleus) increases, attraction is greater and atomic radius is smaller atomic/ionic radii increase ¯ in a group or family
reason 1: # of electrons increase, therefore more orbitals further away from nucleus reason 2: shielding effect - inner electrons shield the valence electrons from the attractive force from nucleus
- weakens the force between nucleus and valence electrons
the positive ion formed when an atom loses its valence electron is smaller than the neutral atom if neutral atom gains, electron, bigger. b/c increase neg charge results in greater mutual repulsion among the electrons - also reduces the attractive force of the nucleus
11-6 Ionization Energy
ionization energy: energy needed to remove an electron from a neutral gaseous atom
Element (g) + ionization energy ® Ion+ (g) + e-
determined in the 1920’s by bombarding gaseous element samples with high energy electrons
energy of bombarding electrons known precisely
when electrons gain enough kinetic energy, atoms start to ionize
first ionization energy - energy needed to eject the most weakly held electron to form pos ion low ionization energy: forms pos ion
high ionization energy: may form neg ions or no ions at all
IE1, IE2, IE3, IE4, IE5, is the energy needed to remove the outermost, next outermost, third, fourth and fifth outermost electrons from the atom, respectively (from valence to inner) IE increase ® in each period / alkali metal low, noble gas high
noble gases the smallest = greater nuclear charge = high energy to rid electron IE2 for Li and He differs even though they both have same electron configuration
reason: Li has nuclear charge of 3+ / He has nuclear charge of 2+
thus greater IE for Li
problems
2. a) x=1, y=3 b) x=3, y=1 or 3 c) x=2, y=4 or 2 d) x=3, y=2 3. a) SrS b)GaF3 c) BeTe d)ClI e) AsBr3
7. 3+, 3