Download Chemistry Chapter 5 The Periodic Law

Chemistry Chapter 5
the Periodic Table

In 1860, Stanislao
Cannizzaro presented
a method for
accurately measuring
the relative atomic
masses of the
elements.
Chemistry Chapter 5
The Periodic Law

In 1869, Dmitri Mendeleev published his first
“periodic table”.
– He started by placing the known elements in order
using their atomic masses.
– He recognized that certain properties repeated
themselves “periodically”.
– He then rearranged the elements so that elements
with similar properties appeared together in his table.
– His procedure left empty spaces for elements that
had not been discovered.
Moseley & the Periodic Law
In 1911, Henry Moseley discovered that
the periodic table fit better when the
elements were placed in order according
to their increasing positive charge.
 This led to the principle of chemical
periodicity known as the:

– periodic law- The physical and chemical
properties of the elements are periodic
functions of their atomic numbers.
The Modern Periodic Table

The periodic table is an arrangement of
the elements in order of their atomic
numbers so that elements with similar
properties fall in the same column, or
group.
– group (or family)- the vertical columns of
the periodic table
– period- the horizontal rows of the periodic
table
The Modern Periodic Table

noble gases- the group 18 elements which are

lanthanides (rare earth elements)-
not reactive (inert)
elements 58-71 at the bottom of the periodic
table that are very similar in properties and
represent the 4th energy level “f” orbital block
elements from period 6.
 actinides- elements 90-103 are all radioactive
and represent the 5th energy level “f” orbital
block elements from period 7.
– Do section review #3 & 5 on page 137.
Section Review- page 137
3-
The noble gases, the lanthanides , and
the actinides have been added. They
were not yet discovered when Mendeleev
wrote the original periodic table and he had
no way of predicting their existence.
5-
The periodic table is arranged according to
atomic number, not atomic mass. The
average atomic mass on the periodic table is
the weighted average of the isotopes of an
element and some elements have large
percentages of heavy isotopes.
Electron Configuration & the Periodic Table

s-block elements- are groups #1 & #2 in
which a single “s” orbital is being filled in the
energy level equal to the period number.
– alkali metals- are the group #1 metals that are so
reactive that they do not exist as pure elements in
nature
– alkaline-earth metals- are the group #2 metals
that also are very reactive and do not exist alone in
nature
– Do problem #1 on page 143.
Practice problem page 143
1-
What is the period, group and block of
[Kr]5s1 ?
[Kr]5s1 tells us the element rubidium is
in the:
5th period
1st group
s-block
Electron Configuration & the Periodic Table

p-block elements- are groups #13-#18
in which 3 “p” orbitals are being filled in
the energy level equal to the period
number.
– halogens- are the group 17 elements
– noble gases- are the group 18 elements that
are non-reactive (inert)
– Do practice problems #1 & 2 on page 148.
Practice problems page 148
1a-
Write the outer electron configuration of the
group 17 element in the 3rd period.
3s23p5
1b-
Identify the element and identify it as a
metal, metalloid, or nonmetal.
chlorine (Cl)
nonmetal
Practice problems page 148
2a-
What is the period, block and group of the
element
[Ar]3d104s24p3 ?
period 4
p-block
group 15 (5A)
2b-
What is the name of the element and is it a
metal, metalloid or nonmetal?
arsenic (As) is a metalloid
Electron Configuration & the Periodic Table

d-block elements (transition metals)group #3-#12 elements in which 5 “d”
orbitals are being filled in the energy level
equal to the period # minus 1.
– They are metals that have typical metallic
properties.
– Do practice problems #1 & 2 on page 146.
Practice problems page 146
1-
What is the period, group, & block of
element [Ar]3d84s2 ?
period 4
group 10
d block
2-
What is the electron configuration of the
element in group 12 of the fifth period?
[Kr]4d105s2
the
Electron Configuration & the Periodic Table

f-block elements- are the two rows at the
bottom of the periodic table that represent 7 “f”
orbitals being filled in the energy level that is equal
to the period number minus 2
– lanthanides- elements # 58-71 that are also
called the rare earth elements
– actinides- elements #90-103 that are all
radioactive
 elements 93(neptunium) through 103
(lawrencium) are all man-made and do not
occur naturally
Questions

Do Practice problem
#1 on page 149.

Do Section Review
problems #2, 4, & 5.
Practice problem on page 149
For each of the following identify the block, period,
group, group name, element name, element
type, and relative reactivity.
1a-
[He]2s22p5
p-block, period 2, group 17, halogen,
fluorine (F), nonmetal, & highly reactive
1b-
[Ar]3d104s1
d-block, period 4, group 11, transition metal,
copper (Cu), metal, & low reactivity
Section review page 149
2abcde-
group 1 is the alkali metals
group 2 is the alkaline earth metals
groups 3-12 are the transition metals
group 17 is the halogens
group 18 is the noble gases
4-
noble gas electron configuration of the
group 15 period 4 element
[Ar]3d104s24p3
5-
period, block, & group of [Ar]3d74s2
period 4, d-block, group 9
Electron Configuration & Periodic Properties

atomic radius- one-half the distance between
the nuclei of identical atoms that are bonded
together.
– As you go across a period, the positive charge of the
nucleus increases across a period, the pull exerted on
the electron cloud increases and the atomic radius of
the elements decreases across the period.
– As you move down a group, each successive element
adds an energy level so the atomic radii increase
down a group.
Electron Configuration & Periodic Properties

ion- an atom or group of atoms that has
a positive or negative charge
ionization- any process that results in
the formation of an ion

ionization energy- the amount of
energy required to remove one electron
from a neutral atom of an element
– ionization energies of the main group
elements increase across a period
– ionization energies of the main group
elements usually decrease down a group
Electron Configuration & Periodic Properties

electron affinity- the energy change

cation- an ion with a positive charge due

anion- an ion with a negative charge due
that occurs when an electron is acquired
by a neutral atom
to the loss of electrons
to the gain of electrons
Electron Configuration & Periodic Properties

valence electrons- the electrons
available to be gained, lost, or shared by
atoms in the formation of chemical bonds
to make compounds

electronegativity- a measure of the
ability of an atom in a chemical compound
to attract electrons from another atom in
the compound
– electronegativity tends to increase across a
period and either decrease or remain the
same down a group
– fluorine (F) is the most electronegative of the
elements.
Chapter 5 Review

Chapter Review problems pages 166-168
#1, 2, 8, 9, 11, 13, 17, 18, 19, 22, 23,
28, 32, & 40.
Chapter 5 Test Review Exercise
1-
Which elements are called:
aalkali metals
balkaline earth metals
ctransition metals
dhalogens
enoble gases
flanthanides
gactinides
2-
What were the major contributions of:
aDmitri Mendeleev
bHenry Moseley
3-
What is the period number, group number,
block, & identity of the element designated
[Kr]4d105s25p5
4-
What are valence electrons and where are they
found?
5-
What are the period and group trends for the
atomic radius of the elements?
Helpful Hints- Periodic Table Lab
Make note that the sets of elements on page one are in
groups (vertical columns).
 The table is for the “s” and “p” blocks ONLY, no “d” or “f”
block elements are included.
 The clues given are for periods 1 through 4 ONLY.
 The formulas of oxides always end with the element oxygen.
 The elements that are liquid at room temperature are written
in blue on the table at the front of the room.
 The “outer energy level” includes “s” & “p” orbitals ONLY.
 The elements that are gas at room temperature are written in
red on the table at the front of the room.
 The metalloids include B, Si, Ge, As, Sb, & Te.
 Periods 5 & 6 (AA-PP) will be filled out using page 3 of the
lab. Match the element properties with those on appendix A.

Chemistry Chapter 5 Vocabulary Quiz
Monday 11/7/2011
Dmitri Mendeleev
periodic table
period
lanthanides
alkali metals
halogens
atomic radius
ionization energy
cation
valence electrons
periodic law
group
noble gases
actinides
alkaline-earth metals
d-block elements
ionization
electron affinity
anion
electronegativity
Chemistry Chapter 5 Test Review
25 multiple choice questions:
Mendeleev & his 1st periodic table
 Definitions, locations, & properties of lanthanides, actinides,
noble gases, halogens, alkali metals, alkaline earth metals,
& transition metals
 Definitions of periodic law, groups, periods, atomic radius,
electronegativity, cation, anion, & valence electrons
 Where are valence electrons located?
 Period & group trends for atomic radius
 What form do alkali metals take in nature?
 Determine the number of valence electrons for different
groups

Honors Chemistry Chapter 5 Test Review
35 multiple choice questions worth two points each.
Know the definition and inventor (Mendeleev) of the first
periodic table and how he arranged the elements.
 Know how the modern periodic table is arranged and
what groups of elements have been added to it.
 Know the groups and names and unique properties of
the alkali metals, alkaline earth metals, halogens, noble
gases, transition metals, lanthanides, and actinides.
 Know the definition of the periodic law, periods, groups.
 Identify the period & group for a specific element.

next slide
Know the general location of the metals, metalloids, &
nonmetals on the periodic table.
 Why is hydrogen often placed away from the body of the
group 1 elements on a periodic table?
 Know where the s, p, d, & f block element are located
and their meaning.
 Know the definitions of ionization energy,
electronegativity, and atomic radius and their trends
both across a period and down a group.
 Know the definition of valence electrons & how to find
their number in s & p groups.
