Download 12/13/12 Chapter 6 Review: Periodic Table Marcus Holloway

12/13/12
Chapter 6 Review: Periodic Table
Marcus Holloway
Overview:
1. Organizing the Elements
2. Classifying the Elements
3. Periodic Trends
4. Problems / Answers
5. Vocabulary
1. Organizing the Elements
*Many chemists searched for an organizing principle for the periodic table
● chemists began to organize the few known elements
-only 13 elements identified by 1700
-other elements were suspected to exist
● chemists used elemental properties to organize them
-1829: J.W. Dobereiner published a classification system grouping elements
into triads
-there were patterns in his triads such as: one element in each triad had
properties with values that fall in the middle of the other 2
*Mendeleev published a widely accepted periodic table in 1869
● a little while after Mendeleev published his table, another chemist made
one that was nearly identical, but he received less credit because he was
not first
-mendeleev’s table was created as he was trying to show relationships
between over 60 elements in a textbook for his students
● Mendeleev’s periodic table organizes elements by increasing atomic mass
*The modern periodic table is organized by atomic mass and chemical properties
● elements use atomic numbers for organization
*The three broad classes of elements are Metals, Nonmetals, and Metalloids
2. Classifying the Elements
*Periodic table usually displays symbols and names of the elements
● background colors in the squares distinguish groups of elements
*There are noble gases, representative elements, transition metals, or inner
transition metals
● type of element depends on the electron configuration
● noble gases are nonmetals
-called inert gases because they rarely take part in reactions
● representative elements can be metals, nonmetals and metalloids
-there are very few that are gas at room tempurature
● transition metals occupy the highest s sublevel and a nearby d sublevel
with electrons
● inner transition metals occupy the highest level s sublevel and a nearby f
sublevel with electrons
3. Periodic Trends
*Generally, atomic size increases top to bottom (within a group) and decreases
left to right (within a period)
● distances between atoms in a molecule are very small
*Ions with different charges are formed when electrons are transferred between
atoms
● ionization energy increases from left to right across a period and decreases
from top to bottom in a group
*Ionic sizes increase top to bottom in a group and decrease left to right across a
period
*Electronegativity value decreases from top to bottom in a group and
representative elements’ values’ increase from left to right across a period
4.a. Problems
Multiple Choice:
1. Which is not a transition metal?
a. aluminum
b. silver
c. iron
2. In which property does lithium have a larger value than potassium?
a. first ionization energy
b. atomic radius
c. electronegativity
d. ionic radius
3. Which element has a greater electronegativity?
a. cobalt
b. titanium
c. gallium
4. Which element has a larger atomic radius?
a. tungsten
b. iodine
c. aluminum
5. Which element is a nonmetal?
a. titanium
b. magnesium
c. germanium
Short Answer:
1. What are the characteristics of Metals?
2. How many noble gases are there, and what group are they in?
3. What is electronegativity?
4. In which groups are representative metals found?
5. What is the difference between a cation and an anion?
b. Answers
MC:
1. a. aluminum
2. a. first ionization energy
3. a. cobalt
4. c. aluminum
5. b. magnesium
SA:
1. Metals are generally good conductors of heat and electric current.
2. There are 6 noble gases, and they are found in Group 8A (18).
3. Electronegativity is the ability of an atom of an element to attract electrons
when the atom is in a compound.
4. Representative metals are found within Groups 1A (1) - 7A (17).
5. A cation is a positive charged ion and an anion is a negative charged ion.
5. Vocabulary
periodic law: when elements are arranged in order of increasing atomic
number, there is a periodic repetition of their physical and chemical properties.
metals: generally good conductors of heat and electric current
nonmetals: poor conductors of heat and electric current
metalloid: generally has properties that are similar to those of metals and
nonmetals
alkali metals: the elements in Group 1A (1)
alkaline earth metals: the elements in Group 2A (2)
halogens: the nonmetals of Group 7A (17)
noble gases: the elements in Group 8A (18) of the periodic table
representative elements: elements in Groups 1A (1) through 7A (17) - they
display a wide range of physical and chemical properties
transition metals: Group B elements that are usually displayed in the main body
of a periodic table
inner transition metals: elements that appear below the main body of the
periodic table
atomic radius: half the distance between the nuclei of two atoms of the same
element when the atoms are joined
ion: an atom or group of atoms that has a positive or negative charge
cation: an ion with a positive charge
anion: an ion with a negative charge
ionization energy: the energy required to remove an electron from an atom
electronegativity: the ability of an atom of an element to attract electrons when
the atom is in a compound