The Periodic Table Bromfield Honors Chemistry

Organizing information… By the mid-1800’s, about 70 elements

were known Similarities of certain elements

Coinage elements: copper, silver, gold Halogens (“salt-maker”): chlorine, bromine,

iodine Alkali metals: lithium, sodium, potassium

Early attempts at organizing Döbereiner’s triads

Early attempts at organizing Döbereiner’s triads

Newland’s Law of Octaves

Dmitri Mendeleev (1834-1907)

Dmitri Mendeleev (1834-1907) 1869—published first

periodic table of the elements

Dmitri Mendeleev (1834-1907) 1869—published first

periodic table of the elements

Listed all known elements in order of increasing atomic mass

Dmitri Mendeleev (1834-1907) 1869—published first

periodic table of the elements

Arranged rows so that elements with similar properties were side by side

Dmitri Mendeleev (1834-1907) 1869—published first

periodic table of the elements

Arranged rows so that elements with similar properties were side by side (even if out of order by mass)

Dmitri Mendeleev (1834-1907) Left blanks in

table if no element with appropriate property was known

Dmitri Mendeleev (1834-1907) Left blanks in table if

no element with appropriate property was known This led to very

accurate predictions of scandium, germanium and gallium

Henry Moseley (1887-1915) Used x-ray

diffraction data on the elements to determine the nuclear charge

Henry Moseley (1887-1915) Used x-ray

diffraction data on the elements to determine the nuclear charge

Realized that the properties of the elements are related to atomic number

Henry Moseley (1887-1915) Rearranged the

periodic table based on atomic number

Glenn Seaborg Rearranged the

periodic table by putting the lanthanides and actinides under the main body of the table

Video

Modern Periodic Table Periods—

horizontal rows Numbered 1-7

Modern Periodic Table Groups—vertical

columns Convention #1:

Numbered 1-18 Convention #2: numbers

with A/B Convention #3: number s &

p blocks only

“Representative Elements” Elements in groups

1,2, 13-18 Aka “Main group

elements”

Alternative Periodic Tables

Alternative Periodic Tables

Modern Periodic Table Video Most of the elements in the periodic table

are metals!

Classes of elements Metals Typically solids

Exception: mercury

Lustrous Good conductors Malleable Ductile

Nonmetals May be solid,

liquid or gas Solids are brittle Nonconductors

Metalloids Have properties of metals and nonmetals

Group 1—Alkali Metals Most reactive metals Must be stored under oil Not found as free elements in

nature Soft can be cut with a knife

Reactions with water http://www.youtube.com/watch

?v=QSZ-3wScePM

Alkali Metals Typically form +1

ions

Group 2—Alkaline Earth Metals

Group 2—Alkaline Earth Metals Less reactive than

alkali metals

Group 2—Alkaline Earth Metals Less reactive than

alkali metals Not found as free

elements in nature

Group 2—Alkaline Earth Metals Less reactive than

alkali metals Not found as free

elements in nature

Group 2—Alkaline Earth Metals Typically form +2 ions

Transition metals Groups 3-12

Transition metals Compounds of transition metals are

often highly colored

Transition metals Many transition metals can form several

cations Ex. Cr6+, Cr3+

Hemoglobin—a metalloprotein!

Deoxyhemoglobin (in veins) Oxyhemoglobin (near the heme)— In arteries

Inner transition metals Also called the “rare

earths” Lanthanides Actinides

Many are radioactive

Group 16—Chalcogens Tend to form -2

anions Aka “oxygen

family”

Periodic Videos: Selenium

Group 17—Halogens The most reactive

nonmetals Periodic Videos:

Fluorine

Group 17—Halogens The most reactive nonmetals

Tend to form -1 anions

Group 17—Halogens The most reactive nonmetals 7 valence electrons

Tend to form -1 anions Form diatomic molecules

F2, I2, Cl2, Br2

Halogens

Group 18—Noble Gases Non-reactive gases

Open University: Noble Gases Don’t tend to gain or lose

electrons Typically don’t form compounds

The Periodic Law When elements are arranged according

to increasing atomic number, there is a regular and repeating pattern in their chemical and physical properties.

The “Special 7” Elements that exist as diatomic molecules

H2

O2

N2

F2

Cl2

I2

Br2

Other elemental molecules:

P4 S8