Download Unit Five: Periodic Table Families

Unit Five: Periodic Table Families
Unit Goals:
 Examine trends in behavior over period families
 Understand how the periodic table is structured
Warm-up Questions:
“Why do trends occur in the periodic table?”
Assigned Readings:
Glencoe pages 172 – 194, 904 – 945
http://en.wikibooks.org/wiki/General_Chemistry/Periodicity_and_Electron_Configurations
http://en.wikibooks.org/wiki/General_Chemistry/Chemistries_of_Various_Elements/Group_1
http://en.wikibooks.org/wiki/General_Chemistry/Chemistries_of_Various_Elements/Group_2
http://en.wikibooks.org/wiki/General_Chemistry/Chemistries_of_Various_Elements/Group_13
http://en.wikibooks.org/wiki/General_Chemistry/Chemistries_of_Various_Elements/Group_14
http://en.wikibooks.org/wiki/General_Chemistry/Chemistries_of_Various_Elements/Group_15
http://en.wikibooks.org/wiki/General_Chemistry/Chemistries_of_Various_Elements/Group_16
http://en.wikibooks.org/wiki/General_Chemistry/Chemistries_of_Various_Elements/Group_17
http://en.wikibooks.org/wiki/General_Chemistry/Chemistries_of_Various_Elements/Group_18
http://en.wikibooks.org/wiki/General_Chemistry/Chemistries_of_Various_Elements/Hydrogen
http://en.wikibooks.org/wiki/General_Chemistry/Chemistries_of_Various_Elements/Transition_
Metals
Problem Set One:
Assigned Problems:
1. Read all wikibook and textbook sections
2. Write a 2 – 3 paragraph summary of your assigned periodic family. How are the elements
in the family similar?
a. Ammine: Alkali metals
b. Sarah: Alkaline earth metals
c. Basil: Boron family
d. Amirah: Carbon family
e. Farhia: Nitrogen family
f. Dina: Oxygen family
g. Mohammed N: Halogens
h. Aisha: Noble gases
i. Mariam: Hydrogen
j. Aniqa: Coinage metals
k. Mohamed T: Zinc family
l. Nima: Platinum family
m. Fatima: Iron, Cobalt, and Nickel
3. Write three questions related to your periodic family
Problem Set Two:
Assigned Problems:
1.
2.
3.
4.
5.
6.
How many valence electrons does Magnesium have? How many does Calcium have?
How many levels (like two in 2s) does Potassium have? How many does Gallium have?
Which block (s, p, d, or f) is group 2 in? What does that mean?
How many families are in the p-block? How many families are in the d-block? Why?
How many elements are in the d-block?
What element in group one has the largest atomic radius? Which halogen has the smallest
atomic radius? Which one of those is bigger? Why?
7. Which element has the larger ionic radius of these pairs: Why?
a. Li vs. Be
b. N vs. O
c. K vs. Na
8. Use table 6.5 to answer this question. List the ionization energy required to remove one
through five electrons in Carbon. Why does it jump so much at the fifth one?
9. What atom has the most electronegativity? The least electronegativity?
10. Name and explain four reasons for periodic trends. Which one is your favorite?
Lecture Summary:
 Periodic Law
o When arranged in order by atomic mass, elements have repeating chemical and
physical properties
 Periodic table structure
o Columns are called families or groups
 18 families
 Groups 3 to 12 are called the transition metals
o Rows are called periods
 7 periods
o Metals
 Elements towards the left of the table
o Nonmetals
 Elements towards the upper right side of the table
o Metalloids
 Some metallic properties, some non-metal properties
 Between the region of metals and non-metals
o Organized by electron configuration
 Every element in a family has the same number of valence electrons
 All elements in a period have the same quantum number (same level of shells)
 s-Block elements
 Groups 1 and 2 + Helium
 p-Block
 Groups on right of the table
 d-Block
 Transition metals
 f-Block
 Inner transition metals
 Reasons for trends
o Electron shielding


 Electrons block pull from nucleus
o Electron to electron repulsion
 Causes electrons to spread apart
o Coulomb’s Law
 Distance causes decrease in forces on order n2
o Effective nuclear charge
 The nucleus becomes more positively charged with more protons
Periodic trends
o Atomic radius
 Decreases left to right
 Because of increased positive charge in the nucleus
 Increases top to bottom
 Because of additional energy levels added
 As levels are added, close electrons “shield” the charge pull of further
electrons
o Ionic radius
 The more electrons an atom loses, the smaller it gets
 Groups one, two, thirteen and sometimes fourteen get smaller as they
ionize
 The more electrons an atom gains, the larger it gets
 Groups in the p-block get larger to the left as they ionize
 Ionic radius increases as you go down the table
o Ionization energy
 Energy required to remove an electron from an atom
 First ionization refers to removing the first atom, second refers to removing
the second atom, etc
 Increases for each successive atoms; jumps when removing in levels
lower than the valence shell
 Decreases top to bottom
 Electrons are further away from the nucleus
 Increases left to right
o Electronegativity
 Ability to attract electrons
 Decreases from top to bottom
 Increases from left to right
Groups
o Hydrogen
 At STP has lowest density of all gases
 One valence electron
 Shares properties of Alkali metals and Halogens
 Three isotopes
o Alkali Metals
 Group 1
 Silvery, metallic
 Soft
 Very low densities
o
o
o
o
 Low melting points
 Highly reactive; not found in nature in free form
 One valence electron
 Form +1 ions
 Atomic radii and ionic radii increase downwards
 Electronegativity decreases downwards
Alkaline Earth Metals
 Group 2
 Silvery-white, metallic
 Soft, low density
 Density increases down table
 Low melting points
 Two valence electrons
 Forms +2 ions
 Smaller atomic and ionic radii than alkali metals
 Higher electronegativity than alkali metals
Transition Metals
 Groups 3 to twelve
 Good conductors of heat and electricity
 Ductile, malleable
 High densities
 High melting points
 All solid at room temperature except Mercury
 Many paramagnetic: Attracted to magnetic fields
 Some ferromagnetic: Can make their own magnetic field
 More unpaired d electrons = harder, higher melting point, higher density
 Little variation to electronegativity and atomic size due to shielding
 Can lose both s and d electrons to form +1+/2+3 and higher ions
Boron group
 Silvery white, except Boron which is black
 All metals, except Boron is a metalloid
 All are lightweight and soft except Boron which is extremely hard
 All solid at room temperatures
 3 valence electrons, starts filling the p orbital
 All except Boron lose three electrons to form ions
 Some can lose only one to form ions
 Boron only participates in covalent bonding
 Atomic and ion radii increase down the group
 Ionization energy decreases down the group
Carbon Group
 Metallic character increases down the group
 Carbon nonmetal
 Silicon and Germanium are metalloids
 Tin and lead are metals
 Moving down the group melting points decrease
 Large variety of forms and structures available
o
o
o
o
 Allotropes
 Four valence electrons
 Largely covalent bonds; Can give up or gain four
 Atomic and ionic radii increase down the group
 Similar ionization energy and electronegativity throughout group; except
Carbon
 Many real world applications
Nitrogen Group
 Increase in metallic properties as they go down
 Nitrogen and Phosphorous are nonmetals
 Arsenic and Antimony are metalloids
 Bismuth is a metal
 Boiling point and density increase down the table
 Also has large variety of possible physical combinations
 Five valence electrons
 -3, +3, +5 common ion formations
 Ionization energy and electronegative decreases down as you go down the
group
 Atomic and ionic radii increase as you go down the table
Oxygen Group
 All solids at room temperature except oxygen which is a gas
 Common allotropic forms
 Oxygen, sulfur, and selenium are nonmetals
 Tellurium and polonium are metals
 Melting points increase down group, except polonium
 Density increases down the group
 Six valence electrons
 Many different ions formed
 Electronegativity and ionization energy increase going down the group
Halogens
 Fluorine and chlorine are gases at room temperature
 Bromine is liquid
 Iodine is solid
 Melting points increase going down the group
 Seven valence electrons
Noble Gases
 Colorless, odorless gases
 Nonmetals
 Very low melting points; increase down the group
 Eight valence electrons except Helium; stable octet
 Helium has two valence electrons. Full shell, still very stable
 Exist as single atoms
 Highest first ionization; not reactive