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Topic 5
Periodic Table
The Periodic Table
1.
2.
3.
4.
5.
6.
Classifying Elements
a. Mendeleev-according to atomic MASS
7. Properties of Groups
b. Moseley-according to atomic NUMBER
a. hydrogen
Periodic Law
b. Groups 1 & 2-most
Arrangement of the Periodic Table
active metals
a. Period/Series-period number indicates opel
c. Group 17-Halogens
b. Groups/Families-same number of valence e
most active nonmetals
Chemical Symbols-Table S
d. Group 18-Noble Gases
Types of Elements & Characteristics
8 valence e except
a. Metals
He (has 2 valence e)
b. Nonmetals
8. Allotropes
c. Metalloids/Semi-Metals
a. Carbon
d. Noble Gases
b. Oxygen
e. Transition Metals
c. Phosphorus
Properties of Elements-most of the information is on 9. Elements with no stable
Table S
isotopes
a. Ionization Energy (IE)
b. Electronegativity (EN)
c. Atomic Radius
d. Ionic Radius-be able to compare atomic radii vs. ionic radii
As the number of known elements grew, there had to be some
method of organizing this information into a useful table
The first person to organize this information is Dmitri Mendeleev
Dmitri Mendeleev
1834-1907
In 1869, he arranged the elements
according to increasing atomic mass.
Elements in the periodic table are
arranged into groups based on a set of
repeating properties.
There were some inconsistencies
Look at Te (at # 52) and I (at # 53)
Currently, there are 118 elements that make up the Periodic Table
of Elements
When Mendeleev constructed his original table, there were
60 known elements
The Periodic Table of Elements Song
Henry Moseley did not like these inconsistencies and so decides
to arrange the table using another criteria.
Henry Moseley
1887-1915
In 1913, he arranged the elements by
increasing atomic number and now there
were no
inconsistencies.
Each element is represented by a one-or two-letter chemical
symbol. The first letter of a chemical symbol is always
capitalized. When a second letter is used, it is lowercase.
Ex.: carbon
nickel
C
Ni
If you are unsure of the symbol for an element, check Table S
Some elements are represented by three letters.
Their official names have not been determined by IUPAC and
the letters represent their atomic number.
Element 114 called ununquadium - Uuq
Un = one
Quad = four
Properties of Metals
Metals are located to the left of the staircase
More than 2/3 of the elements are metals
1. Good conductors of heat and electricity
2. Ductile-can be drawn into wires
3. Malleable-can be hammered into shape
4. Lose electrons to form positive ions (cations)
5. Luster -shiny
6. Solid at room temperature
except mercury (Hg) liquid
Periodic Law-When elements are arranged in order of increasing
atomic number, there is a periodic repetition of their
physical properties.
Rows (left  right) are called periods or series
Look at your periodic table and look at the seven periods.
The period number is the outermost principle energy
level (opel) for that element
Ex.: Si
Look at what row it is in
Row 3 = opel
Columns (up and down) are called groups or families
Elements in the same group have similar chemical
properties because they have the same number of valence eLook at the lower left hand corner of the box of any
element. The last number is the number of valence eEx.: Si 2-8-4
There are 4 valence electrons
Properties of Nonmetals
Nonmetals are found to the right of the staircase BUT do not
include Group 18 elements
1. Insulators-do not conduct heat and electricity
2. Brittle-shatter when hammered
3. Gain electrons to form negative ions (anions)
4. Most are gases at room temperature, a few are solid
and only one is a liquid (Br) at room temperature
Properties of Metalloids
A metalloid is an element that tends to have properties that are
similar to those of both metals and nonmetals
Metalloids sit right along the staircase. A side
of the element’s box must touch the staircase to be a metalloid
The metalloids are B, Si, As, Te, At, Ge and Sb
Notice Al and Po have a side of their box touching the staircase,
but they are NOT metalloids
Properties of Noble Gases-Group 18
Their opel (outermost principle energy level) is filled with electrons.
All of the noble gas elements have 8 valence electrons except for
helium which has 2 valence electrons
Because they have a filled opel, they are unreactive
Look in the upper right hand corner of the box of Ne
The 0 indicates that it is unreactive
Now look at the box for Kr and Xe
Notice the numbers…this means that they do react
What type of element do noble gases react with?
Elements with small atomic radius & high electronegativity
Elements like Fluorine
Properties of Transition Elements
Groups 3-12
The highest occupied sublevel and nearby d or f sublevel contain
electrons.
Solutions made of compounds that contain a transition element
will have color
Ex.: CuSO4 will have color because Cu is
a transition element
Do not forget your seven diatomic elements
BrINClHOF
Br2
I2
N2
Cl2
H2
O2
F2
Diatomic elements-a molecule consisting of two atoms
The rest of the elements are monatomic
Monatomic elements-a molecule consisting of one atom
Properties of Elements
Ionization Energy- The energy required to remove an electron
from an atom in its gaseous state
As you move left to right across a period, IE increases because
nuclear charge increases (at. no. increases) and shielding effect
remains constant so it takes more energy to remove an electron
As you move down a group, IE decreases because there is an
additional energy level, (size of element increases) so shielding
effect is greater. Therefore, less energy is needed to remove an
electron
Electronegativity- The ability of an atom to attract electrons
when the atom is in a compound
As you move across a period EN increases because nuclear charge
increases and shielding effect remains constant so the nucleus is
able to attract electrons better.
As you move down a group EN decreases because there is an
additional energy level, (size of element increases) so shielding
effect is greater. Therefore, the nucleus is not able to attract
electrons easily
Atomic Radius
One-half the distance between the nuclei of two atoms of the same
element when the atoms are joined
As you move across a period, the radius decreases because nuclear
charge increases and shielding effect remains constant so the
nucleus is able to pull the electrons in closer
As you move down a group, the radius increases because there is
an additional energy level, (size of the element increases) so
shielding effect is greater. Therefore, the element is larger.
Ionic Radius
When a metal atom loses an electron to become a cation,
the radius of the ion is less than the radius of the atom
Ca > Ca+2
The more electrons lost or the fewer energy levels, the smaller the
ion
When a nonmetal atom gains an electron to become an anion,
the radius of the ion is greater than the radius of the atom
S < S2The more electrons gained or the more energy levels, the larger
the ion
Summary of Periodic Trends
Across a period
Ionization Energy increases
Electronegativity increases
Atomic Radius decreases
Why?
Nuclear charge increases but shielding effect remains constant.
Down a group
Ionization Energy decreases
Electronegative decreases
Atomic Radius increases
Why?
Additional energy level so size of atom increases and shielding effect
increases
Properties of Groups
Group 1-Alkali Metals
Most reactive metals. Never found uncombined in nature.
Always found combined with other elements
Group 2-Alkaline Earth Metals
Slightly less reactive than Group 1 metals. Never found
uncombined in nature. Always found combined with other
elements
Group 17-Halogens
Most reactive nonmetals. Never found uncombined in nature.
Always found combined with other elements
Only group with three phases of matter:
F & Cl = gas
Br = liquid
I = solid
Group 18-Noble Gases
Filled valence shell-therefore very unreactive
Group 15
Triple bond between nitrogen molecules
Group 16
Double bond between oxygen molecules
Groups 1 & 2- s-block elements
Opel contains electrons in the s orbitals only
Groups 3-12- d-block elements
Outer electron configuration contains electrons
in the d orbitals
Group 13-18p-block elements
Outer electron configuration contains electrons
in the p orbitals
Lanthanide & Actinide Series- f-block elements
Outer electron configuration contains electrons
in the f orbitals
Allotropes
One of two or more different molecular forms of an element in
the same physical phase/state.
Ex.:
Carbon in the solid state
Graphite (solid-pencils)
Diamond
Oxygen in the gaseous state
O2 (oxygen)
O3 (ozone)
Phosphorus in the solid state
Red phosphorus Black phosphorus
Yellow/White phosphorus
Same phase but different molecular structure and therefore
different physical and chemical properties
Remember:
Sublimation- Phase change from solid to gas with
no visible liquid phase
Deposition- Phase change from gas to solid with no visible liquid
phase
What are the two substances that sublime?
CO2 (dry ice) & I2 (iodine)
Elements with atomic number 83 and below have
some stable isotopes and some unstable isotopes
Elements with atomic number 84 and above have no stable
isotopes. All of their isotopes are radioactive.
f-block elements
Lanthanide series
Actinide series
Properties of Metals
1. Luster
2. Low Electronegativity
3. Low Ionization Energy
4. Malleable
5. Ductile
6. High melting point
7. High boiling point
8. Conductor of heat/electricity
9. Lose electrons (+ ions)
10. Francium (Fr)-best/most
reactive metal
Properties of Nonmetals
1.
2.
3.
4.
5.
6.
7.
8.
9.
High Electronegativity
High Ionization Energy
Brittle
Low melting point
Low boiling point
Dull
Insulators
Gain electrons (-ions)
Fluorine (F)-best/most
reactive nonmetal
The New Periodic Table Song