Transcript THE PERIODIC TABLE - Los Angeles City College

THE PERIODIC TABLE
• is arranged in order of increasing number of
protons.
• the atomic number of an element is the
number of protons in the nucleus and the
number of electrons in a neutral atom.
• the atomic weight increases with increasing
number of protons and neutrons.
• the atomic weight is the average weight of all
the isotopes of that element (the average of the natural
abundance x mass number).
THE PERIODIC TABLE
• is divided into metals (left side), nonmetals
(right side), and metalliods.
• is arranged in rows (across) in order of
increasing energy levels of valence electrons
(called periods). The period number
represents the energy level for that row.
• is arranged in columns (down) in order of
similar orbitals for the valence electrons
(called groups).
• The elements are represented by one or two
letter symbols, which have some correlation to
the element name.
THE PERIODIC TABLE
Metals
Nonmetals
• Located on the left side of
the periodic table
• Tends to lose electrons to
form cations
• Has low ionization energies
& electronegativity values
• Forms compounds with
nonmetals but not other
metals
• Good conduction of heat and
electricity
• Lustrous & malleable solids
excepts Hg which is a liquid
• Ductile
• Located on the right side of
the periodic table
• Tends to gain electrons to
form anions
• Has high ionization
energies &
electronegativity values
• Forms compounds with
both metals and nonmetals
• Poor conduction of heat
and electricity
• Non-lustrous & brittle or
gaseous
• Non-ductile
THE PERIODIC TABLE
• is divided into "blocks" which represent the
orbital the electron occupies; s, p, d, and f.
• is read left to right; 1s, 2s, 2p, 3s, 3p, 4s....
• is arranged as representative elements (s and
p block elements), transition metals (d block
metals), lanthanides and actinides (f block
metals).
• is arranged in order of increasing energy of the
subshells; the lowest energy level is always
filled first.
• the noble gases are unreactive since they have
a completely filled shell and are the lowest in
energy.
THE PERIODIC TABLE
• Groups or families display similar physical and
chemical reactivity.
• the group number (roman numerals) on top
represents the number of valence electrons
available for that column.
• common groups are:
group I = alkali metals
group II = alkaline earth metals
group VI = chalogens
group VII = halogens
group VIII = noble or inert gases
THE PERIODIC TABLE
• demonstrates the trends in atomic
properties; the periodicity of the
elements.
– Atomic radius,
– ionization energy,
– electronegativity,
– magnetism
are some of the properties of atoms
which can be predicted using the
periodic table.
THE PERIODIC TABLE
• Atomic radius
In general, the atomic radii of
the elements within a row
(period) decreases from left
to right due to an increase in
nuclear charge whereas the
radii increases down a
column (group) due to the
addition of electrons in
higher energy levels.
decreases
i
n
c
r
e
a
s
e
s
THE PERIODIC TABLE
• Electronegativity
Electronegativity describes the
ability of an atom to attract
electrons to itself in a
chemical bond. It is the
attractive force that one atom
has for a shared pair of
electrons of a different atom
in a covalent bond. Notice
that the electronegativity can
be related to the ionization
energy and electron affinity.
increases
d
e
c
r
e
a
s
e
The
electronegativity
generally
increases
across a
period and
decreases
down a
group.
Periodic Table of the Elements
H
2.1
Electronegativity
Li Be
1.0 1.5
B C N O F
2.0 2.5 3.0 3.5 4.0
Na Mg
0.9 1.2
Al Si P S Cl
1.5 1.8 2.1 2.5 3.0
K Ca
0.8 1.0
Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br
1.3 1.4 1.6 1.6 1.5 1.8 1.8 1.8 1.9 1.6 1.6 1.8 2.0 2.4 2.8
Rb Sr
0.8 1.0
Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I
1.2 1.4 1.6 1.8 1.9 2.2 2.2 2.2 1.9 1.7 1.7 1.8 1.9 2.1 2.5
Cs Ba
0.7 0.9
La - Lu
1.1-1.2
Fr Ra
0.7 0.9
Ac - Lr
1.1-1.7
Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At
1.3 1.5 1.7 1.9 2.2 2.2 2.2 2.4 1.9 1.8 1.8 1.9 2.0 2.2
PRACTICE PROBLEMS about the PERIODIC TABLE
Classify the elements as representative, transition, lanthanide, or
actinide.
1. Cd
2. Te
3. Sr
4. Al
5.Gd
6. Rh
7. Cf
8. Be
9. Pd
10. O
4. Se
5. Br
Classify the elements by the group name:
1. Be
2. Rb
3. Xe
Arrange in order of increasing electronegativity.
C
O
Be
N
Sr
S
B
Arrange in order of increasing atomic radius.
C
O
Be
N
Sr
S
B
ANSWERS
Classify the elements as representative, transition, lanthanide, or
actinide.
1. Transition
2. Representative
5. lanthanide 6. transition
9. transition
3. representative 4. representative
7. actinide
8. representative
10. Representative
Classify the elements by the group name:
1. Alkaline earth
2. alkali
3. noble
4. chalogen
Arrange in order of increasing electronegativity.
Sr < Be < B < S = C < N < O
Arrange in order of increasing atomic radius.
O < N < C < S
< B < Be < Sr
5. halogen