How are

most

library

books

classified?

Why is such a

classification

system

useful?

Chapter 6 and 7

The Periodic Table

and Periodic Law Harry Potter Sings the Element

Song

Jim Lehrer The Real Periodic

Table Song

1789 - Lavoisier

Acid making

phosphorous

sulfur

carbon

Gas like

light

heat

oxygen

Azote (nitrogen)

hydrogen

1789 - Lavoisier

Metallic

Copper, nickel, iron

Cobalt, mercury, tin

Gold, lead, silver, zinc

Earthy

Lime (calcium hydroxide)

Magnesia (magnesium oxide)

Manganese, tungsten

(platina) platinum

Barytes (barium sulphate)

Argilla (Aluminum oxide)

Silex (silicon dioxide)

I. Development of the Modern

Periodic Table 6.1 pg. 151-158

1. Compiled a list of 23 elements known

at the time.

2. 1800’s: changes in the world

3. Electricity used to break compounds,

spectrometer, industrial revolution

4. Tripled Lavoisier’s number of elements

5. 1860 chemists agreed on atomic masses

A. Lavoisier – 1790’s

B. John Newland - 1864 1. Proposed an organization scheme

2. Arranged by increasing atomic mass

3. The elements’ properties repeated

every eighth element

4. The law of octaves.

Musical Analogy

B. John Newland - 1864

C. Meyer, Mendeleev, & Moseley

1. Meyer & Mendeleev each demonstrated connections between atomic mass and elemental properties.

2. Mendeleev published first and showed the connections’ usefulness

3. Mendeleev predicted the existence and properties of undiscovered elements.

4. He left blanks for undiscovered elements

Can you find the errors in his system?

C. Meyer, Mendeleev, & Moseley

"...if all the elements be arranged in order of their atomic

weights a periodic repetition of properties is obtained." -

Mendeleev

Mendeleev’s First Periodic Table

5. Henry Moseley (1913):

British chemist - discoveries resulted in a

more accurate positioning of elements

by determination of atomic numbers.

(Tragically for the development of

science, Moseley was killed in action at

Gallipoli in 1915).

5. Moseley (continued)

5. When atoms were arranged according to

increasing atomic number, the few problems

with Mendeleev's periodic table had

disappeared. Because of Moseley's work, the

modern periodic table is based on the atomic

numbers of the elements

6. Periodic Law: There is a periodic repetition of

the chemical and physical properties of the

elements when they are arranged by increasing

atomic number.

5. Moseley

BCC History of the

Periodic Table

II. The Modern Periodic Table

A. Columns on the periodic table are

called groups or families.

Atomic number increases as you

move down on the periodic table.

Each group is numbered one though

eight, followed by the letter A or B.

II. The Modern Periodic Table

What group is Chlorine in? VIIA

B. The rows on the periodic table are called periods.

Each row on periodic table (except the first) begins with a metal and ends with a noble gas.

Beginning with hydrogen in period 1 there are a total of seven periods. In between, the properties of the elements change in an orderly progression from left to right.

The pattern in properties repeats after group VIIIA (18).

II. The Modern Periodic Table

C. Why does the first period on the periodic table only have two elements?

Only two electrons can occupy the first energy level in an atom.

The third electron in lithium must be at a higher energy level.

Lithium is the first element in Group IA and in Period 2.

II. The Modern Periodic Table

D. The groups designated with an A (IA through VIIIA) are often referred to as the main group or representative elements because they possess a wide range of chemical and physical properties.

The groups designated with a B (IB through VIIIB) are referred to as the transition elements.

II. The Modern Periodic Table

Vanadium a transition element.

II. The Modern Periodic Table

III. Classification of the Elements

A.Valence Electrons

1. electrons in the highest principal

energy level

2. What would group IA look like?

3. Atoms in the same group have

similar chemical properties because

they have the same number of

valence electrons.

B. The s-, p-, d- and f- block elements

1s1, 2s1….

III. Classification of the Elements

A. Metals are elements that have luster, conduct heat and electricity, and usually bend without breaking, and are solid at room temperature. With the exception of tin, lead, and bismuth, metals have one, two, or three valence electrons.

III. Classification of the Elements

The metals

Metals are to the left of the heavy stair-step line that zigzags down from Boron (B, in column IIIA) to astatine (At) at the bottom of group VIIA (hydrogen is the exception). Alkali metals – group IA, the most reactive of all metals. They react with water to form alkaline solutions.

III. Classification of the Elements

Alkali metals

Alkaline earth metals group IIA. These elements form compounds with oxygen, called oxides. All transition elements are metals.

III. Classification of the Elements

All transition elements are metals.

III. Classification of the Elements

Inner transition metals are know as lanthanide and actinide series and are located along the bottom of the periodic table. Because of their natural abundance on Earth is less than 0.01 percent, the lanthanides are sometimes called the rare earth elements. All of the lanthanides have similar properties.

III. Classification of the Elements

All of the actinides are radioactive, and none beyond uranium (92) occur in nature.

III. Classification of the Elements

Meet Dr. Glenn Seaborg

B. Nonmetals are elements that are generally gases or brittle, dull-looking solids. They are poor conductors of heat and electricity.

The only liquid nonmetal at room temperature is bromine (Br).

The highly reactive group VIIA is the halogens, “salt formers.” The extremely un-reactive group is the noble gases.

The nonmetals oxygen and nitrogen make up 99 percent of Earth’s atmosphere.

III. Classification of the Elements

Carbon, another nonmetal, is found in more compounds than all the other elements combined.

Their melting points tend to be lower than those of metals.

III. Classification of the Elements

C. Metalloids or semimetals.

Metalloids are elements with

physical and chemical properties

of both metals and nonmetals.

Silicon and germanium are tow of

the most important metalloids as

they are used extensively in

computer chips and solar cells.

III. Classification of the Elements

Some metalloids such as silicon,

germanium (Ge), and arsenic

(As) are semiconductors.

III. Classification of the Elements

A semiconductor is an element that

does not conduct electricity as well

as a metal, but does conduct slightly

better than a nonmetal.

The ability of a semiconductor to

conduct an electrical current can be

increased by adding a small amount

of certain other elements.

III. Classification of the Elements

Silicon’s semi conducting properties made the computer revolution possible.

III. Classification of the Elements

Your television,

computer, handheld

electronic games, and

calculator are electrical

devices that depend on

silicon semiconductors.

All have miniature electrical circuits that use silicon’s properties as a semiconductor.

You learned that metals generally are good conductors of electricity, nonmetals are poor conductors, and semiconductors fall in between the two extremes.

III. Classification of the Elements

The ability of a semiconductor to conduct an electrical current can be increased by adding a small amount of certain other elements.

Silicon’s semi conducting properties made the computer revolution possible.

Your television, computer, handheld electronic games, and calculator are electrical devices that depend on silicon semiconductors.

III. Classification of the Elements

III. semiconductors

What clues does the arrangement of the football players on the

field give about the functions of their positions?

What characteristics does a football player have based on the

position played?

V. Periodic Trends 6.3 pgs. 163-169

A. Atomic Size or Radius

1. How closely an atom lies to a neighboring atom.

2. Metals – half the distance between two adjacent atoms in a crystal

3. Nonmetal – determined from a diatomic molecule of an element

Time out!

What’s a

diatomic

element?

Time out! What’s a diatomic

element?

Mr. Brinklehoff

BrINClHOF

gases

N2, H2, F2…

an element that when not

chemically bonded with any other

elements, will form a molecule

having two atoms of the element.

A. Atomic Radii - trend (cont.)

Size increases going across – right to left. (Across same energy level, but add protons and the ‘pull’ of nucleus is greater and pulls electrons closer.)

Size increases going down a group. Electrons are at progressively higher levels, and shielding effect is increasing.

A. Atomic Radii (continued) Shielding Effect – lots of inner electrons

shield or protect the outer electrons from the ‘pull’ of the positive nucleus.

What happens to shielding effect as

you go down the periodic table? increases

What happens to shielding effect as

you go across the periodic table?

Stays the same

B. Ionic Radius

Positive ions are always smaller than

neutral atoms

+1 +2 +3

-1 -2 -3

Negative ions are always larger than

neutral atoms because their nuclear

attraction is less

Going down a group – both anions and

cations get bigger

Going across: + decrease, - increase

Smaller Larger

Atomic and ionic radii trends

C. Ionization Energy

Energy required to remove an

electron from a gaseous atom.

Think of ionization energy as an

indication of how strongly an atom’s

nucleus holds onto its valence

electrons.

Bigger your ionization energy the

harder it is to rip an electron away.

How easy is it to become an ion?

Ionization energy

I.E. increases going up (harder to pull off outer

electrons when atoms are smaller)

I.E. increases going across (harder to pull off

electrons because of nuclear attraction is

hanging onto them.

Metals have lower I.E., nonmetals have high I.E.

High High

Successive ionization energies

D. Electronegativity

indicates the relative ability of an

atom to attract electrons in a

chemical bond “hogs electrons”

The bigger the electronegativity

the bigger the ‘hog’

Polar Covalent Bonds

Though atoms often form

compounds by sharing

electrons, the electrons

are not always shared

equally.

• Fluorine pulls harder on the electrons it

shares with hydrogen than hydrogen does.

• Therefore, the fluorine end of the molecule

has more electron density than the hydrogen

end.

Electronegativity Electronegativity is the

ability of atoms in a

molecule to attract

electrons to themselves.

On the periodic chart,

electronegativity increases

as you go…

…from left to right across a

row.

…from the bottom to the

top of a column.

D. Electronegativity (continued)

moving across, electronegativity increases

moving up electronegativity increases

high highest

Video Electronegativity

Following Slides not covered in chapter 6

Glencoe

E. Electron Affinity

“Electron Grabbiness” or how easy it is

for an atom to gain electrons (make a

negative ion = anion)

(-) negative = energy released

(+) positive = energy absorbed

Electron Affinity

E. Electron Affinity (continued)

Generally decreases going down a group

because atomic size increases

Increases going across because atoms are

smaller and nucleus charge increases

F. Melting Points metallic side – decreases as you go down

non-metals- increase going down

melting pt of gases are very low (-100 C)

G. Metallic Character

increase to left and down least

metallic

most

metallic

Metallic Character

H. Chemical Activity

metals – increase going down, most active? Cs

non metals – decreases going down, most active?

F