The Periodic
Properties of the
Elements
By Lauren Querido, Chris Via,
Maggie Dang, Jae Lee
The Founders of the Periodic
Table
Luthar Meyer
http://chemheritage.org/classroom
/chemach/images/lgfotos/04perio
dic/meyer-mendeleev2.jpg
Dmitri Mendeleev
http://nuclphys.sinp.msu.ru/perso
ns/images/mendeleev.gif
7.1 Developing the Periodic Table
 Dmitri Mendeleev (1869)- and Luthar
Meyer Published very similar documents
to classify the elements. And were the
first to make the modern periodic table

Used chemical and physical properties to
classify
 Henry Moseley (1887-1915)- Developed
concept of atomic numbers

Found that frequency increases as the
atomic mass increases
7.2 Electron Shells and Size of
Atoms
 Electron Shells in Atoms

Gilbert N. Lewis – electrons are arranged
in shells surrounding the nucleus.
 Atomic sizes
-http://grandinetti.org/Teaching/Chem121/Lectures/PeriodicTrends/assets/radiitable.gif

Bonding Atomic
Radius- the distance
between the center
of two bonding
atoms
http://www.chembook.co.uk/fig13-1.jpg
Practice Problem #1
 Predict the lengths of C-S, C-H, and S-H
bonds in this molecule
 Radius of C = 0.77 Å
 Radius of S = 1.02 Å
 Radius of H = 0.37 Å
 When determining the bonding radius,
you add the radius of the bonding atoms
together
Answer to Practice Problem #1
 C-S bond length = radius of C + radius of
= 0.77 Å + 1.02 Å = 1.79 Å
 C-H bond length = 0.77 Å + 0.37 Å = 1.14 Å
 S-H bond length = 1.02 Å +0.37 Å = 1.39 Å
7.2 continued
 When moving across a row, the number
of core electrons stay the same but the
nuclear charge increases
 The effective nuclear charge increases
even though the quantum number
remains the same
 Shielding is the process of blocking the
protons effective charge on the
outermost electrons
7.3 Ionization Energy
 Ionization Energy – to remove an
electron from the ground state
 Second Ionization – removing the 2nd
electron from the ground state
 I1<I2<I3 and so forth; It increases in
magnitude
 The greater effective nuclear charge, the
greater the ionization energy
7.3 cont..

There is a sharp increase in ionization
energy when an inner shell electron is
removed
 Periodic Trends
1. Within each row, the ionization energy
increases with atomic number
2. Within a group, the ionization energy
generally decreases with increasing
atomic number
7.3 cont..
3. The ionization energy of transition elements & fblock metals increase slowly as you read from
left to right.
 The transition in ionization energy are affected
by how strong an electron is attracted to an
atom
 It is affected by the effective nuclear charge and
the average distance from the nucleus.
7.3
 The irregularities are explained through
the periodic table
 Electrons in the s orbital are more
effective at shielding than in the p orbital
7.4 Electron Affinities
 Positive ionization energy = energy put
into atom in order to remove electrons
 Electron affinity = attraction of change in
energy when the electron is added
 Most atoms = energy is released when
electron is added
 A positive electron affinity, an ion will not
form
7.4 cont..
 On the periodic table, electron affinity
becomes negative towards halogen
(closest to being stable)
 The electron affinity does not change
when they move down a group (noble
gases)
http://www.meta-synthesis.com/webbook/35_pt/best_PT-form.jpg
Element Classification
http://www.elementsdatabase.com/Images/periodic_table1.gif
7.5 Metals, Nonmetals, and
Metalloids
 Metals


Tend to have low ionization energies and
lose electrons when they undergo
chemical reaction
Most metal oxides are basic oxides that
dissolve in water react to for metal
hydroxides
Metal Oxide + Water  Metal Hydroxide

Metal oxides show their basicity by
reacting with acids to form water and salts
Metal Oxide + Acid  Salt + Water
7.5
 Characteristics of Metals





Have a shiny luster
Various colors
Solids are malleable and ductile
Good conductors of heat and electricity
Most metal oxides are ionic solids that are
basic
7.5
 Nonmetals

Tend to gain electrons and become anions
Metal + Nonmetal  Salt

Most nonmetal oxides are acidic oxides
that dissolve in water react to form acids
Nonmetal Oxide + Water  Acid

The acidity of nonmetal oxides is shown by
the fact they dissolve in basic solutions to
form salts
Nonmetal Oxide+ Base  Salt + Water
7.5
 Characteristics of Nonmetals





Do not have a luster
Various colors
Solids are usually brittle; some are hard,
and some are soft
Poor conductors of heat and electricity
Most nonmetallic oxides are molecular
substances that form acidic solutions
7.5
 Metalloids

Have properties intermediate between
nonmetals and metals
http://www.rkm.com.au/METALLOIDS/metalloidimages/METALLOID-SILICON-500.jpg
7.6 Group Trends for the Active
Metals
 Group 1A: The Alkali Metals (most
active)

Metallic Characteristics
 Silvery
 Metallic
luster & high thermal
 Electrical conductivities
 Have low densities & melting points
 Very reactive b/c they want to lose 1 electron
to form ions with a 1+ charge so it becomes
more stable
7.6 cont..
 As you move down a group


Atomic radius increases
1st ionization energy decreases
7.6 cont..
 Group 2A: The Alkaline Earth Metals

Properties of Alkaline Earth Metals
 Harder
 More
Dense
 Melt at higher temps
 Highly Reactive

Compared to alkali Metals, Alkaline Earth
metals..
lower 1st ionization energies
 Are less reactive
 Have
7.7
 Group 6A
 Oxygen is a colorless gas at room
temperature while all the other elements
in this group are solid.
 Oxygen has two main forms:
02=“oxygen” and 03=“ozone”.
 This is an example of an allotrope, it has
different forms of the same element.
7.7
 The most stable form
of sulfur is S8, It is a
yellow solid.
 All of the elements in
this group have the
tendency to gain
electrons form other
elements.
 http://www.science.u
waterloo.ca/~cchieh/
cact/fig/s8.gif
7.7
 Group 7A: Halogens
 Halogens is named Greek words, “halos” and
“gennao” meaning salt formers.
 Fluorine and Chlorine are gases, bromine is a
liquid, and iodine is a solid at room
temperature.
 These elements melting and boiling points
increase with atomic number.
 These elements have highly negative electron
affinities because they have the need to gain
electrons from other elements.
The Fluorine atom is very reactive!
http://www.chemistryland.com/ElementarySchool/BuildingBlocks/Fl
uorineAttracts.jpg
7.7
 Group 8A: Noble Gases
 All of the elements are nonmetals at
room temperature and they are
monatomic
 They are very unreactive because they
have completely filled s and p orbitals.
 They also have very large 1st ionization
energies.
That’s All Folks