Transcript The Periodic Table

The Periodic Table
Elements are arranged in groups
based on properties
The Periodic Table
Dmitri Mendeleev
arranged the
elements
according to
atomic mass
and used the
arrangements
to predict the
properties
of missing
elements.
The Periodic Table
 The modern periodic table is arranged
in order of increasing atomic number.
 The atomic number is the total number
of protons in the nucleus.
 The electron mostly determines the
properties of an element.
The Periodic Table
 Indium:
 ______ protons
______ electrons
 49
49
The Periodic Table
 GROUPS vertical columns
 Old 1A - 8A new 1 - 18
 Periods - horizontal
rows
 Magnesium is in the
same group as
calcium.
 Magnesium is in the
same period as
phosphorus.
The three
classes of
elements
are:
metals,
nonmetals,
and
metalloids.
The Periodic Table
 Metals include the majority of the
elements.
Pt is a metal.
Si is a metalloid.
Kr is a nonmetal.
 Metals are shiny, malleable (hammered
into sheets), ductile (drawn into wires),
solid at room temperature, and good
conductors of electricity.
The Periodic Table
 Nonmetals are
poor conductors of electricity,
often gases at room temperature,
and brittle if solid.
 Metalloids have some properties of
metals and nonmetals.
Group 1A - alkali metals
Group 2A - alkaline earth metals
Group 7A - halogens
Group 8A - noble gases
Groups 1A through 7A representative elements
Group B - transition metals
The Periodic Table
 Aluminum is a representative element.
 Copper is a transition metal.
 Na is an _______________________
 Mg is an _______________________
 F is a ________________________
 Ne is a ______________________
 Ag is a ______________________
The Periodic Table
 Na is an alkali metal
 Mg is an alkaline earth metal
 F is a halogen
 Ne is a noble gas
 Ag is a transition metal
The Periodic Table
 There are 5 electrons in the valence
level of an element in Group 5A.
 N, P, As, and Sb have the same number
of electrons in their valence levels.
The Periodic Table
 The electron configuration for an
element in the halogen group should
always end with ns2np5.
 The electron configuration of the
element chlorine ends in 3s23p5.
The Periodic Table
 Noble gases (inert gases) have their
highest occupied s and p sublevels
filled.
 Fe contains an electron in a d sublevel.
Atomic size
 The atomic radius increases from top
to bottom in a group in the periodic
table.
 As you move down a group in the
periodic table, atomic size generally
increases
Atomic size
 The atomic radius decreases from left
to right across a period in the periodic
table.
 Lithium has the largest atomic radius in
the second period.
 As the number of electrons added to
the same energy level increases,
atomic size generally decreases.
Atomic size
 List the symbols for sodium, sulfur, and
cesium in order of increasing atomic
radii _____________________ The
largest atom in Group 1A is
______________
 The smallest atom in Group 7A is
______________
Atomic size
 List the symbols for sodium, sulfur, and
cesium in order of increasing atomic
radii: S, Na, Cs
 The largest atom in Group 1A is Fr.
 The smallest atom in Group 7A is F.
Ions & Ionization
 Ions form when electrons enter or leave
atoms.
Ions & Ionization
 The charge of a cation is positive.
Cations are smaller than the original
atom.
 An anion has a negative charge. Anions
are larger than the original atom.
Ions & Ionization
 Removing one electron from an atom
results in the formation of an ion with a
1+ charge.
Ions & Ionization
 Ionization energy - energy required to
move an electron out of an atom
 Ionization energy decreases from top to
bottom and increases from left to right
on the periodic table.
Ions & Ionization
 Among Na, K, and Cs, which element
has the lowest ionization energy?
 Which is larger, K or K+?
 Which is smaller, Li, Li+, F, or F- ?
Ions & Ionization
 Among Na, K, and Cs, which element
has the lowest ionization energy?
Cs
 Which is larger, K or K+?
K
 Which is smaller, Li, Li+, F, or F- ?
Li+
Electronegativity
 Electronegativity is
the ability of an
atom in a compound
to attract electrons
Electronegativity
 Electronegativity values tend to decrease from
top to bottom and increase from left to right.
Electronegativity
 Which element in each pair has a




higher electronegativity value?
Mg, Ne
Cl, F
C, N
As, Ca
Electronegativity
 Which element in each pair has a




higher electronegativity value?
Mg, Ne
Mg
Cl, F
F
C, N
N
As, C
As
Electronegativity
 Cs has one of the lowest
electronegativity values.
Electronegativity
 Valence (outer) electrons may be
transferred from one atom to another.
 Group
Valence
electrons
 1A
Lose 1
 2A
Lose 2
 3A
Lose 3
Resulting
charge
1+
2+
3+
5A
6A
7A
Gain3
Gain 2
Gain 1
321-
Electronegativity
What charge would Na likely have in a
compound? _______
What charge would Mg likely have in a
compound? _______
What charge would Al likely have in a
compound? _______
Electronegativity
 What charge would Na likely have in a
compound? 1+
 What charge would Mg likely have in a
compound? 2+
 What charge would Al likely have in a
compound? 3+
Electronegativity
 What charge would O likely have in a
compound? _______
 What charge would F likely have in a
compound? _______
Electronegativity
 What charge would O likely have in a
compound? 2-
 What charge would F likely have in a
compound? 1-