THE PERIODIC TABLE

Objective: Explain the use of chemical and physical properties in the historical development of the Periodic Table.■ Antoine Lavoisier: In the 1700’s complied a list of all know elements (33) organized

into 4 categories.

– Gases (light, heat, inflammable air, etc.)

– Metals (antimony, silver, arsenic, bismuth, zinc, etc.)

– Nonmetals (sulfur, phosphorus, pure charcoal, etc.)

– Earths (chalk, clay, siliceous earth, etc.)

■ John Newlands: In 1864 he noticed that when the elements were arrange in order

of increasing ATOMIC MASS that the properties REPEATED EVERY 8 ELEMENTS.

– This pattern is called PERIODIC.

– Called this the Law of Octaves.

– Not accepted because did not work for all elements and “octave” sounded

“unscientific.”

Dmitri Mendeleev: 1869Father of The Periodic Table

■ Also noticed that when the elements were arranged by atomic mass that there was a Periodic Pattern in their properties.

■ His table had vertical rows and horizontal columns.

■ The Columns had SIMILAR PROPERTIES.

■ Left BLANK SPACES for undiscovered elements.

■ Predicted the properties for:

– scandium

– gallium

– germanium

■ Lothar Meyers demonstrated the same connection but Mendeleev was FIRST.

Henry Moseley (1887 – 1915)

■ Problems with Mendeleev’s table:

– As new elements were discovered did not fit

pattern.

■ Henry Moseley discovered that each element had a

UNIQUE NUMBER OF PROTONS.

■ This is the ATOMIC NUMBER.

■ In 1913 he proposed that the Period Table be

organized by Atomic Number which gave a CLEAR

Period Pattern.

■ PERIODIC LAW: There is a periodic repetition of

chemical and physical properties of the elements

when they arranged by increasing ATOMIC NUMBER.

■ MODERN PERIODIC TABLE

■ Vertical Columns:

– Groups or Families

– 18 groups

■ Horizontal Rows:

– Periods

– 7 periods

■ Representative Elements:

– groups 1, 2, 13-18

■ Transition Elements:

– groups 3-12

– Inner Transition Metals

■ Also classified as:

– metals

– nonmetals

– metalloids

The Modern Periodic Table

■ Objective: Use the

Periodic Table to

identify and explain

the properties of

chemical families

including alkali

metals, alkaline

earth metals,

halogens, noble

gases, and

transition metals.

Electron Arrangements

Alkali Metals

■ Family 1

■ Most active of all the metals

■ One valance electron in outer most energy level. (ns1: Li –1s22s1, Na – 1s22s22p63s1)

■ Lose the one valance electron when forming chemical bonds.

■ Form +1 ions.

■ All atoms “want to have an octet of valance electron so they will gain lose or share electrons to get to this “magic number.”

Alkaline Earth Metals

■ Family 2.

■ Second most active of the

metals.

■ Two valance electrons (ns2: Be

– 1s22s2, Mg – 1s22s22p63s2)

■ Lose 2 valance electrons when

forming chemical bonds.

■ Form +2 ions.

Transition Metals■ Group 3 – Group 12

■ Less active than alkali or alkaline earth metals.

■ One or two valance electrons. All transition metals have ns1 or ns2

valance electron structures.

■ They have (n-1)d1 – (n-1)d10.

■ They have oxidations (ion charges) of +1 through +7.

■ Transition metals do not obtain octets because they have “d” electrons involved in bonding.

Boron Family

■ Family 13

■ Boron – metalloid

■ Aluminum and rest are metals.

■ 3 valance electrons.

■ ns2np1

■ +3 ion charge

Carbon Family■ Family 14

■ Carbon – nonmetal

■ Silicon and germanium are metalloids.

■ Tin and lead are metals.

■ 4 valance electrons.

■ ns2np2

■ Carbon and silicon can be +4 or -4 or it

can share electrons to form bonds.

■ Tin and lead can be +2 or +4.

Nitrogen Family■ Family 15

■ Nitrogen and phosphorus are

nonmetals.

■ Arsenic and antimony are metalloids.

■ Bismuth is a metal.

■ 5 valance electrons.

■ ns2np3

■ Nitrogen and phosphorus are usually -

3.

■ Bismuth and antimony are +3 or +5.

Oxygen Family

■ Family 16

■ Oxygen, sulfur and selenium are

nonmetals.

■ Tellurium and polonium are

metalloids.

■ 6 valance electrons.

■ ns2np4

■ Oxygen and sulfur are usually -2.

Halogens■ Family 17.

■ Most active of the nonmetals.

■ 7 valance electrons (ns2np5: F – 1s22s22p5, Cl – 1s22s22p63s23p5)

■ Gain 1 electron to obtain octet.

■ Form -1 ions.

■ Halogens is Greek for salt former; they form salts when reacting with metals.

Noble Gases (Inert Gases)

■ Family 18.

■ Most inactive of all elements.

■ Do not normally form compounds.

■ 8 valance electrons (ns2np6: Ne –1s22s22p6, Ar – 1s22s22p63s23p6)

■ A perfect octet of electrons so they do not gain or lose electrons to form compounds.

■ Helium is only 1s2, but it still does not form compounds because the 1st

energy level is filled with only 2 electrons.

Periodic TrendsObjective: Use the Periodic Table to identify and explain periodic trends, including atomic and ionic radii, electronegativity, and ionization energy.

Atomic Radius: One half the distance between 2 adjacent atoms.

Ionization Energy Electronegativity

Energy required to remove an electron from an atom

The relativity of an atom to attract electrons in a chemical bond.

Periodic Trends

Ionization Energy GraphAtomic # 1 2 3 4

1 H 1,312

2 He 2,372 5,251

3 Li 520.3 7,298 11,815

4 Be 899.5 1,757 14,849 21,007

5 B 800.7 2,427 3,660 25,026

6 C 1,086 2,353 4,621 6,223

7 N 1,402 2,856 7,475 9,445

8 O 1,314 3,388 5,301 7,469

9 F 1,681 3,374 6,051 8,408

10 Ne 2,081 3,952 6,122 9,370

11 Na 495.9 4,563 6,913 9,544

12 Mg 737.8 1,451 7,733 10,541

13 Al 577.6 1,817 2,745 11,578

14 Si 786.5 1,577 3,232 4,356

15 P 1,012 1,903 2,912 4,957

16 S 999.6 2,251 3,361 4,564

17 Cl 1,251 2,297 3,822 5,158

18 Ar 1,521 2,666 3,931 5,771

19 K 418.9 3,051 4,412 5,877

20 Ca 589.8 1,145 4,912 6,474

The Periodic Law

■ Date: October 23 / October 24

■ Partners:

■ Problem: Can the properties of elements on

the periodic table be predicted by measuring

the same properties for other elements in the

same family?

■ Hypothesis:

Procedures

■ 1. Use a spot plate to determine the

solubilities of the alkaline earth metals.

■ 2. React: magnesium nitrate, calcium nitrate,

strontium nitrate, and barium nitrate;

■ with: ammonium oxalate, sulfuric acid,

sodium carbonate, and potassium chromate.

Procedures■ 3. Determine the mass and volume of

elements in the carbon family: silicon, tin, and

lead.

■ 4. Calculate the densities for each element.

Results:Data Table

C2O4-2 SO4

-2 CO3-2 CrO4

-2

Mg+2

Ca+2

Sr+2

Ba+2

Results:Data Table

mass

(g)

volume

(cm3)

density

(g/cm3)

silicon

tin

lead

Results:Graph

■ Create a graph representing the density of

elements in family 14.

■ Density will be the dependent variable and

atomic number will be the independent

variable.

■ Use the graph to predict the density of

germanium (atomic number 32)

Results:Calculation

■ Calculate the error for the density of germanium.

■ Experimental Error =

■ | Actual density – Experimental Density | X 100

■ Actual Density

■ Actual Density of Ge = 5.32 g/cm3

Conclusion

■ Conclusion:

■ Restate problem and hypothesis.

■ What is the pattern for change in solubility for the

alkaline earth metals?

■ Predict the solubility of beryllium and radium.

■ What is the pattern for change in density for family

14?

■ Predict the density of germanium.