PART 1: the Periodic Table and Physical Properties

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

NOTES - Unit 3: Periodicity

PART 1: The Periodic Table and Physical Properties

______: elements with same number of valence electrons and therefore similar chemical and physical properties; vertical column of elements (“family”)

______: elements with same outer shell; horizontal row of elements

______: regular variations (or patterns) of properties with increasing atomic weight. Both chemical and physical properties vary in a periodic (repeating pattern) ______.
Periodic Groups

alkali metals
alkaline earth metals
transition metals
halogens
noble gases
lanthanides
actinides

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

Alkali Metals

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

•Group _____ on periodic table

•Called alkali metals because they all react with water to form an alkali solution of the metal hydroxide and hydrogen gas.

–i.e. ______

•React by losing outer electron to form the metal ion

•Good ______agents (because they can readily lose an electron)

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

Alkaline Earth Metals

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

•Group ______on periodic table

•Abundant metals in the earth

•Not as reactive as alkali metals

•Higher density & melting pt. than alkali metals

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

Transition Metals

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

•Variable valency & ______state

•Forms ______compounds

•Forms ______

•______behavior

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

Halogens

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

•Group _____ on periodic table

–group 17 or VIIA on other P.T.’s

•React by ______more electrons to from halide ions

•Good ______agents (because they readily gain an electron)

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

Noble Gases

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

•Group ______(or 8) on periodic table

–group 18 or VIIIA on other P.T.’s

•Sometimes called rare gases or inert gases

•Relatively ______

•______at room temperature

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

Lanthanides

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

•Part of the “inner transition metals”

•Soft silvery metals

•Tarnish readily in air

•React slowly with water

•Difficult to separate because all have two effective valence electrons

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

Actinides

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

•______elements

•Part of the “inner transition metals”

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

Periodic Trends: properties that have a definite trend as you move through the Periodic Table

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

•Valence Electrons

•Atomic radii

•Ionic radii

•Electronegativity

•Ionization energy

•Melting points

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

Valence Electrons:

The electrons in the outermost electron ______(highest energy level) are called valence electrons.

“______”= Latin to be strong

Most chemical reactions occur as valence electrons seek a stable configuration.

(______energy level, and to a lesser extent ______)

Non Valence electrons are called “______electrons”. Core electrons are relatively stable.

Example: Chlorine (Cl) – 17 total electronsExample: Cadmium (Cd) – 48 total electrons

For the tall groups the

column number is the

number of valence electrons.

General Concepts: electron attraction to the nucleus depends on…

______

______

______

Atomic Radii

The atomic radius is the distance from the nucleus to the outermost electron.
Since the position of the outermost electron can never be known precisely, the atomic radius is usually defined as ______between the nuclei of two bonded atoms of the same element.
Thus, values not listed in IB data booklet for ______.
Trend: ______
WHY???
The atomic radius gets bigger because electrons are added to energy levels ______away from the nucleus.
Plus, the inner electrons shield the outer electrons from the positive charge (“pull”) of the nucleus; known as the ______
Trend: ______
WHY???
As the # of protons in the nucleus increases, the positive charge increases and as a result, the “pull” on the electrons increases.

Ionic Radii

Cations (+) are always ______than the metal atoms from which they are formed. (fewer electrons than protons & one less shell of e’s)

Anions (-) are always ______than the nonmetal atoms from which they are formed. (more electrons than protons)

•Trend: For both cations and anions, ______

•WHY???

•Outer electrons are farther from the nucleus (more ______)

•Trend: For both cations and anions, ______

•WHY???

•The ions contain the same number of electrons (______), but an increasing number of protons, so the ionic radius decreases.

First Ionization Energy: The energy to remove one outer electrons from a gaseous atom.

•Trend: ______

–WHY???

•Electrons are in ______energy levels as you move down a group; they are further away from the positive “pull” of the nucleus and therefore easier to remove.

•As the distance to the nucleus increases, Coulomb force is reduced. (Remember from Physics the ______nature of the force)

•Trend: ______

–WHY???

•The increasing charge in the nucleus as you move across a period exerts ______“pull” on the electrons; it requires more energy to remove an electron.

Electronegativity:a relative measure of the attraction that an atom has for a shared pair of electrons when it is covalently bonded to another atom.

•Trend: ______

•WHY???

•Although the nuclear charge is increasing, the ______produced by the added energy levels means the electrons are farther away from the nucleus; decreased attraction, so decreased electronegativity; plus, shielding effect

•Trend: ______

•WHY???

–______, atomic radius is ______; attractive force that the nucleus can exert on another electron increases.

Melting Point

Depends on both…

______
______

Trend (using per 3 as an example):

•Elements on the ______exhibit metallic bonding (Na, Mg, Al), which increases in strength as the # of valence electrons increases.

•Silicon in the ______of the period has a macromolecular covalent structure (network) with very strong bonds resulting in a very high melting point.

•Elements in ______(P4, S8 and Cl2) show simple molecular structures with weak van der Waals’ forces (more on that next unit) of attraction between molecules (which decrease with molecular size).

•The ______(Ar) exist as single individual atoms with extremely weak forces of attraction between the atoms.

Within groups there are also clear trends:

In ______the m.p. ______as the atoms become larger and the strength of the metallic bond decreases.
In ______the van der Waals’ attractive forces between the diatomic molecules increase down the group so the melting points ______.

PART 1 Practice Problems:The Periodic Table and Physical Properties

Fill in the table below with the period and group numbers as they are listed on the IB Periodic Table of Elements:

Element / Period (#) / Group (# and name if appropriate)
Helium
Chlorine
Barium
Francium

How many valence electrons are present in the atoms of the element with atomic number 51?

Describe and explain the trend in radii of the following ions: O2-, F-, Ne, Na+, Mg2+

Explain why the magnesium ion is much smaller than the magnesium atom.

Rank the following elements in order of increasing electronegativity: Sr, Cl, Al, P, Cs

Provide an explanation for trend determined in question number 4.

Explain why carbon has the highest melting point in its period

Which of the following properties increase from sodium to argon?
Nuclear charge
Atomic radius
electronegativity

PART 2: The Periodic Table and Chemical Properties of Groups 1 & 7

Group 1 – the alkali metals

React by losing an electron (good reducing agents; tend to be oxidized)
Reactivity increases down the group as the outer electron is in successively higher energy levels and less energy is therefore required to remove it.
Called “alkali metals” because all react with water to form an alkali solution of the metal hydroxide and hydrogen gas.
Alkali metal + water  metal hydroxide (base) + hydrogen gas
Reactions you should know: Li, Na, K + H2O

All react with chlorine, bromine and iodine to form ionic salts
Alkali metal + halogen gas  metal halide (salt)
Reactions you should know: Li, Na, K + I, Br, Cl

Group 7 – the halogens

React by gaining electrons (good oxidizing agents; tend to be reduced)
Reactivity decreases down the group as the outer shell is increasingly at higher energy levels and further from the nucleus. This, together with the fact that there are more electrons between the nucleus and the outer shell (more shielding), decreases the attraction for an extra electron.
Since chlorine is a stronger oxidizing agent than bromine, it can remove the electron from bromide ions in solution to form chloride ions and bromine. Similarly, both chlorine and bromine can oxidize iodide ions to form iodine.
Reactions you should know: Cl, Br, I + Cl-, Br-, I- (none will react with Cl- since it is most reactive)

Test for halide ions

The presence of halide ions in solution can be detected by adding silver nitrate solution.
This works well because all silver halides are insoluble in water and have characteristic colors.
Ag+ + halide ions (X-)  AgX(s), where X = Cl, Br or I
AgCl = white
AgBr = cream
AgI = yellow
Silver halides react with light to form silver metal. This is the basis of photography.
AgX(s) + light Ag(s) + ½X2

PART 3: Oxides and chorides of the third period (sodium  argon)

Oxides of period 3 elements

Formula / Na2O / MgO / Al2O3 / SiO2 / P4O10
(P4O6) / SO3
(SO2) / Cl2O7
(Cl2O)
State at 25°C
Melting pt. (°C)
Boiling pt. (°C)
Electrical conductivity in molten state
Structure
Rxn w/ H2O
Nature of oxide

Explanation of trends of per 3 oxides

Physical properties - melting points, boiling points & conductivity: (from left  right)

Left side of PT: oxides of Na, Mg and Al = ionic (metal + nonmetal… large difference in electronegativity)
Ionic solids have high melting points
Ionic solids are capable of conducting electricity in molten state (moving charge = electricity)
Middle of PT: oxide of Si (silicon dioxide) = macromolecular structure
Strong diamond-like structure (covalently bonded network) accounts for high boiling point
Right side of PT: oxides of P, S and Cl = simple covalent molecules
difference in electronegativities between element and oxygen is small
low melting and boiling points

Chemical properties - Acid-base nature of oxides: (from left  right)

Oxides of electropositive (opposite of electronegative) elements are very basic and form alkaline solutions
Na2O(s) + H2O(l) 
MgO(s) + H2O(l) 
The amphoteric nature of aluminum oxide can be seen from its rxns w/ hydrochloric acid (a strong acid) and sodium hydroxide (a strong base)
Acting as a base:

Acting as an acid:

Silicon dioxide behaves as a weak acid. It does not react with water (that would be weird… SiO2 is sand, so if sand chemically reacted with water then our beaches would be very different places). However, silicon dioxide will form sodium silicate with sodium hydroxide (meaning it reacts with a base).
SiO2(s) + 2NaOH(aq) 
The oxides of phosphorus, sulfur and chlorine are all strongly acidic (all form strong acids when added to water).
SO2(s) + H2O(l) 

P4O10(s) + H2O(l) 

Cl2O7(l) + H2O(l) 
Chlorides of period 3 elements

Formula / NaCl / MgCl2 / Al2Cl6 / SiCl4 / PCl3
(PCl5) / S2Cl2 / Cl2
State at 25°C
Melting pt. (°C)
Boiling pt. (°C)
Electrical conductivity in molten state
Structure
Rxn w/ H2O
Nature of solution

Explanation of trends of per 3 chlorides

Physical properties - melting points, boiling points & conductivity:(from left  right)

Structure affects physical properties of chlorides in the same way it did for oxides.
NaCl and MgCl2 are ionic – conduct electricity in molten state – high melting points
AlCl3 is covalent – poor conductor
Unlike SiO2, SiCl4 has a simple molecular structure (not a macromolecular network)
PCl3, PCl5, S2Cl2, Cl2 – all have simple molecular structures (covalently bonded molecules)
held together by weak van der Waals’ forces, resulting in low melting and boiling points.

Chemical properties - Acid-base nature of chlorides: (from left  right)

NaCl dissolves in H2O to give a neutral solution (more on why when we get to the acid/base unit).
MgCl2 gives a slightly acidic solution with water (again, more on this later).
All other chlorides including AlCl3react vigorously with water to produce acidic solutions of hydrochloric acid together with fumes of hydrogen chloride.
___AlCl3(s) + ___H2O(l) 

SiCl4(l) + ___H2O(l) 

PCl3(l) + ___H2O(l) 

Chlorine itself reacts with water to some extent to form acidic solution.
Cl2(g) + H2O(l) 

PART 4: d-block elements (first row)

The first row transition elements: electron configurations are [Ar]…

(Sc) / Ti / V / Cr / Mn / Fe / Co / Ni / Cu / (Zn)

Note: for Cr and Cu it is more energetically favorable to half-fill or completely fill the d sub-level so they have only one 4s electron

Oxidation states of the first row transition series: (you need to be familiar with the ones in bold)

(Sc) / Ti / V / Cr / Mn / Fe / Co / Ni / Cu / (Zn)
+1
+2 / +2 / +2 / +2 / +2 / +2 / +2 / +2 / +2
+3 / +3 / +3 / +3 / +3 / +3 / +3 / +3 / +3
+4 / +4 / +4 / +4 / +4 / +4 / +4
+5 / +5 / +5 / +5 / +5
+6 / +6 / +6
+7

Transition element: an element that possesses an incomplete d sub-level in one or more of its oxidation states.

Based on the above definition, which of the elements above are not transition elements? Explain.

Characteristic properties of transition elements:

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

______
______
______
______

Unit 3: PeriodicityIB Topics 3 & 13AP Chapters (Zumdahl): 7.12-7.13; 19.2; 21.1-21.3; & pp. 906, 922 AP Chapters 1-5

Variable oxidation states

______and ______sublevels are similar in energy
Transition metals lose their ____-electrons first
The ______increase in ionization energy from losing the last 4s election to the first 3d election explains the existence of ______.
All transition metals can show an oxidation number of ______.
Some transition metals can form the ______or ______ion
Fe3+
Mn4+
The M4+ ion is ______and in higher oxidation states the element is generally found not as the free metal ion, but either ______bonded or as the oxyanion, such as MnO4-.
Some common examples of variable oxidation states in addition to +2 follow:

Transition element / Oxidation # / Formula / Name
Cr / CrCl3
Cr / Cr2O72-
Mn / MnO2
Mn / MnO4-
Fe / Fe2O3
Cu / Cu2O

Formation of complex ions

Ions of the d-block elements attract species that are rich in electrons (ligands) because of their ______size.
The electron pair from a ______can form ______covalent bonds (a.k.a. “dative” - a bond in which both shared electrons are supplied by one species… remember Lewis Bases from Honors Chem?) with the metal ion to form ______.
Ligand: ______

______

The word “ligand” is derived from ______, the Latin word for “bound”
Most (but not all) transition metal ions exist as ______complex ions in aqueous solutions
[Fe(H2O)6]3+
Ligands can be replaced by other ligands (such as ______or ______).

Coordination number: the number of ______bonded to the metal ion.
Examples:state the coordination numbers of the species below.

[Fe(CN)6]3-[CuCl4]2-[Ag(NH3)2]+

More examples: fill in the ligand, coordination number and oxidation number in the table below.

Complex / Ligand / Coordination number / Oxidation number of central ion / Shape (more on
this next unit)
Fe(H2O)6]3+ / octahedral
[CuCl4]2- / tetrahedral
Co(NH3)6]3+ / octahedral
[Ag(NH3)2]+ / linear
MnO4- / tetrahedral
Ni(CO)4 / tetrahedral
PtCl2(NH3)2 / square planar

Colored complexes

In the free ion, the five______are degenerate (of equal energy). However, in complexes the d orbitals are split into ______.
The energy difference between the levels corresponds to a specific ______and ______in the ______region of the electromagnetic spectrum.
When the complex is exposed to light, energy of a specific wavelength is ______and electrons are excited from the ______level to the ______level.
Cu2+(aq) appears blue because it is the ______to the wavelengths that have been absorbed.
The energy separation between the orbitals and hence the color of the complex depends on the following factors:
______(based on identity of the central metal ion)
______
Ex: NH3 has a higher charge density than H2O and so produces a larger split in the d sublevel.
[Cu(H2O)6]2+ absorbs red-orange light and appears ______blue
[Cu(NH3)4(H2O)2]2+ absorbs the higher energy yellow light and appears ______blue
Number of ______present (and hence the oxidation # of the central ion)
______of the complex ion
Electric field created by the ligand’s lone pair of electrons depends on the geometry of the complex ion
If the d sublevel is completely empty, as in Sc3+, or completely full, as in Cu+ or Zn2+, no transitions within the d sublevel can take place and the complexes are ______.
NOTE: it is important to distinguish between the words “clear” and “colorless.” Neither AP,nor IB, will give credit for use of the word clear (which means translucent) when colorless should have been used. Think about it, something can be pink and clear… colorless means something else.

Catalytic behavior

Many transition elements and their compounds are very efficient catalysts.
Catalysts______.
Examples: (need to be familiar with examples and economic significance of those in bold, but mechanisms will not be assessed)
Fe in the Haber Process(p. 906)

V2O5 in the Contact Process(p. 922)

Ni in the conversion of alkenes to alkanes

Pd and Pt in catalytic converters

MnO2 in the decomposition of hydrogen peroxide

Fe2+ in heme

Co3+ in vitamin B12