Transcript The Periodic Table

The Periodic Table
Alkali metals Highly reactive metals in
group 1A of the periodic table
Alkaline earth metals Fairly reactive
metals in group 2A of the periodic table
Transition metals Those elements found
in the d block of the periodic table whose properties
tend to be less predictable based simply on their
position in the table
Halogens families Highly reactive
nonmetals in group 7A of the periodic table
Noble gases The group 8A elements, which
are largely unreactive (inert) due to their stable filled
p orbitals
The Periodic Table
Atomic radii A measure of the size of an
atom
Ionic radii A measure of the size of an atoms
ion in a crystal lattice form
Electronegativity The ability of an atom to
attract electrons to itself
Ionization energy The energy required to
remove an electron from an atom or ion in its
gaseous state
Knowing the Periodic Table
Rows are referred to as periods
Columns are referred to as families or groups
Elements within a group generally have
similar properties
When elements are arranged in order of
increasing atomic number, there are recurring
physical and chemical properties  Periodic
law
States of Matter at Room
Temperature
Development of the Periodic
Table
The number of known elements drastically
increased in the early 1800s
In 1869, Dmitri Mendeleev from Russia and
Lothar Meyer form Germany published
classification systems
Mendeleev is given credit for organizing
elements into the periodic table
Development Cont.
The periodic table is an arrangement of elements
in which they are separated into groups based on
repeating properties
Mendeleev arranged the elements in order of
increasing mass (there were some exceptions Ex.
Te and I)
It was later realized that arranging by properties,
rather than mass was more accurate
Mendeleev left gaps for undiscovered elements,
but accurately predicted their properties
Modern Periodic Table
In the early 1900’s Henry Moseley
determine atomic numbers of each
known element
The modern table is arranged based on
increasing atomic numbers
Each period on the periodic table
corresponds to a principal energy level
Elements with similar chemical and
physical properties end up in the same
column
Main Chemical Families
Alkali Metals
Alkaline Earth Metals
Transition Metals
Halogens
Noble gases
Properties of Alkali Metals
(Group 1)
Have metallic properties of metals
Shiny luster, malleability, high thermal and electrical conductivity
Soft solids at room temperature, low melting points and
densities
Very reactive! (Especially with water)
Found as compounds in nature, never as free elements
Lose an electron when they react, thus have a +1 oxidation
state
Properties of Alkaline Earth
Metals (Group 2)
Soft metals
Very reactive! (Less reactive than alkali metals)
All except beryllium (Be) react with water
Most occur naturally only in compounds
When reacted, they give up 2 electrons and have a
+2 oxidation state
Properties of Transition
Metals (Groups 3-12)
Most transition metals have common metallic
characteristics with other elements in their families ;
except zinc (Zn), cadmium (Cd), and mercury (Hg)
Can exist in several common oxidation states
Are likely to form complexes with unbalanced
charges and excessive electrons
Properties of Halogens
(Group 17)
All halogens are nonmetals
Generally poor conductors of heat and electricity
Are not all found in the same state of matter
The only family with all 3 states of matter
At room temperature, fluorine (F) and chlorine (Cl) are gases.
Bromine (Br) is a liquid. Iodine (I) and astatine (At) are solids.
Very reactive (will even react with glass!)
Halogens are commonly found as diatomic molecules (F2, Cl2)
Gain an electron when reacted; oxidation state of -1
Properties of Noble Gases
All gases at room temperature
Odorless and colorless
Very low reactivity
Exist as unbound elements in nature
Referred to as inert (nonreactive)
Trends of Atomic Radii
Size of atoms is expressed as the atomic radius
Atomic radii generally decrease from left to right across
a period and increase from top to bottom of a group
Principal quantum number (n) of outer-level electrons
increases by one from period to period
Ex. Elements in period 1, n=1. For period 2, n=2, and so on
As n increases down a family, the average position of outerlevel electrons is farther from the nucleus
As a result, atoms are LARGER
Trends of Ionic Radii
Ion atom or group of atoms with a charge
Cation atoms that have lost 1 or more e- and have a +
charge
Cations are smaller in radius because they have lost eEx. Ca2+ is smaller than Ca because it has lost 2 e-
Anion atoms that have gained 1 or more eAnions are larger because they have gained eEx. Br- is larger than Br because it has one more e- orbiting
Trends of anions and cations are similar to that of their
neutral atomic radii
Electronegativity Trend
Number of protons and the principal
quantum number influence electronegativity
Generally, electronegativity increases from left
to right across a period (because the # of p+
increases)
It generally decreases from top to bottom of a
group (due to outer energy level e- being
farther from the nucleus
Ionization Energy Trend
In the event of multiple e- being removed from an
atom, there are different ionization energies
corresponding to each e- removed
The energy required to remove the first e- is referred
to as the “first ionization energy”
Generally, ionization energy increases from left to
right across a period and decreases from top to
bottom within a family
Ionization Energy Cont.
Depends on the force of attraction
the nucleus exerts on the eAlso depends on # of p+ and
distance of e- from the nucleus
The more p+ force, the more difficult
to remove an e-
Atomic Radii Practice
Arrange the following elements in order
of increasing atomic radii
Sodium
Iron
Potassium
Sulfur
Phosphorus
Ionic Radii Practice
Arrange the following ion in decreasing
order of ionic radii
Mg2+
FCu2+
Li+
O-
Electronegativity Practice
Which of the following atoms is more
electronegative? Which is less?
Calcium
Chlorine
Explain why you chose ___ as more
electronegative than ___.
Ionizing Energy Practice
Do metals or non-metals have a higher
ionizing energy?
List the following elements in order of
increasing ionizing energy
Au
Co
Pd