The Periodic Table

I. HistoryII. Arrangement of ElementsIII. Electron Configuration

TrendsIV. Periodic TrendsV. Reactivity

Mendeleev (1834-1907- Russian) (father of modern periodic table)Published system used today (1869)2. Elements arranged by increasing mass3. Left spaces for elements not yet discovered - predicted properties (scandium, gallium, germanium)

Dimitri Mendelev

E. Henry Mosley (1887-1915) English1.Arrange elements

by increasing atomic number – this led to the periodic law

2. Periodic Law - properties

of elements are periodic

functions of their atomic #

periodic repetition of

physical and chemical

properties

II. Arrangement of Elements

A. Periodic Table – arrangement of elements in order of increasing atomic number so that elements with similar properties are in the same column

period – horizontal row (7)

group(family)- vertical columns (1-18)

periodicity – reoccurrence of similar

properties of elements in groups

C. Special Groups on the Periodic Table

Periodic Table

D. Periodic Table Showing s,p,d,f Blocks

E. Metals – Metalloids - Nonmetals

1. Metals are on the left side – all are solids

except mercury (Hg)

a. elements near the left of a period are more metallic than those near the right

b. elements near the top of a group are more metallic than those near the bottom

2. Metalloids – group of elements between

metals and nonmetals(B,Si,Ge,As,Sb,Te)

3. Nonmetals are on the right side – all are

solids or gases except bromine(Br) liquid

Metals – Metalloids - Nonmetals

PROPERTY METAL NONMETAL

Luster high low

Deformability malleable brittle

and ductile

Conductivity good poor

Electron gain/lose lose gain

Ion formed cation (+) anion(-)

Ionization energy low high

Electronegativity low high

IV.Periodic Trends(Main Group Elements)

A. Atomic Radii 1. atomic radius is ½ the distance between nuclei of identical atoms joined in a molecule 2. decreases across periods (left-right) a. caused by increasing attraction between protons and electrons 3. increases from top to bottom a. caused by adding electrons to new shells

What is the atomic radius?

Atomic radii include the region in which electrons are found 90% of the time

Atomic Size

•Atomic Radius = half the distance between two nuclei of a diatomic molecule.

}Radius

Periodic Trends in Atomic Radii

Periodic Trends in Atomic Radii

Trends in Main Groups

Atomic Radii Period Trends

A. Periodic Trends in Atomic Radii

B. Ionization Energy

1. Energy required to remove an electron from an atom of an element (KJ/mol)2. Increases across periods (left to right) a. result of increased nuclear attraction3. Decreases down groups (families) a. electrons added to higher energy levels b. shielding effect of inner shell electrons c. repulsion of inner shell electrons4. Energy to remove second and third

electron is greater

B. Trend in Ionization Energy

B. Periodic Trends in Ionization Energy

Symbol First Second Third

HHeLiBeBCNO F Ne

1312 2731 520 900 800 1086 1402 1314 1681 2080

5247 7297 1757 2430 2352 2857 3391 3375 3963

11810 14840 3569 4619 4577 5301 6045 6276

C. Electronegativity1. Measures how strongly one atom

attracts the electrons of another atom when they form a compound

2. Increases across periods (left to right)

a. Fluorine has greatest value of 4

3. Decreases down groups

a. electrons far from the nucleus in

larger atoms have less attraction

b. Cesium and Francium with large radii

have the smallest electronegativity

Periodic Trends in Electronegativity

C. Periodic Trends in Electronegativity

C. Periodic Trends in Electronegativity

D. Ionic Radii1. Ion – atom that acquires a charge by

gaining or losing electrons

a. cation (+) ion anion (-) ion

2. Period trends

a. cation radii decrease across periods

b. anion radii increase across periods

3. Group trends

a. increase in cation and anion radii

down groups

Formation of an Anion (- ion)

D. Comparison of Atomic and Ionic Radii

D. Periodic Trends in Ionic Radii

E. Electron Affinity

1. Energy change that occurs when an electron is added to a neutral atom

2. If it is easy to add an electron to an

atom the energy value is negative

a. halogens have large negative values

3. If it is difficult to add an electron to an

atom the energy value is positive

a. atoms in groups 2 and 18 have high

positive values (due to filled subshells)

b. usually higher values in larger atoms

Electron Affinity for Chlorine

Periodic Trends in Electron Affinity

Periodic Trends in Electron Affinity

PERIODIC TRENDS

Periodic Trends in Melting Point

Periodic Trends in Density

V. Reactivity

A. Reactivity – measure of the tendency of an element to engage in chemical reactions by losing, gaining or sharing electrons

1. atoms of reactive elements are very

likely to gain, lose or share electrons

2. atoms of reactive elements are likely to form chemical bonds with other elements

B. Reactivity and the Periodic Table 1. alkali metals (group 1) most reactive metals 2. alkaline earth metals (group 2) second most reactive group of metals 3. halogens (group 17) most reactive nonmetals 4. noble gases (group 18) least reactiveC.Ionization Energy and Electronegativity 1. elements with very high and very low values are very reactive

Electron Arrangement and Reactivity

Electron Configuration

• S block [groups 1 and 2]

• P block [groups 13,14,15,16,17,18]

• D block [groups 3,4,5,6,7,8,9,10,11,12]

• F block (lanthanide and actinide series)

1s1 group 1

1s22s1

1s22s22p63s1

1s22s22p63s23p64s1

1s22s22p63s23p64s23d104p65s1

1s22s22p63s23p64s23d104p65s24d10

5p66s1

1s22s22p63s23p64s23d104p65s24d105p66s2

4f145d106p67s1

H1

Li3

Na11

K19

Rb37

Cs55

Fr87

• Alkali metals all end in s1

• Alkaline earth metals all end in s2

• Should include He but helium has the properties of the noble gases.

- its outer shell is filled with the

maximum number of electrons

allowed for the first shell (2)

s2s1 S- block

He2

Ne10

Ar18

Kr36

Xe54

Rn86

1s2

1s22s22p6

1s22s22p63s23p6

1s22s22p63s23p64s23d104p6

1s22s22p63s23p64s23d104p65s24d105p6

1s22s22p63s23p64s23d104p65s24d10

5p66s24f145d106p6

The P-block p1 p2 p3 p4 p5 p6

Transition Metals -d block

d1 d2 d3s1

d5 d5 d6 d7 d8s1

d10 d10

F - block• inner transition elements- hold a maximum

of 14 therefore there are 14 elements in both the actinides and lanthanides

f1 f5f2 f3 f4

f6 f7 f8 f9 f10 f11 f12 f14

f13

Group Ion Formed Electron Changes

• Group 1 X+

• Group 2 X2+

• Group 13 X3+

• Group 14 Xvaries

• Group 15 X3-

• Group 16 X2-

• Group 17 X-

• Group 18 X0

• Loses 1 electron

• Loses 2 electrons

• Loses 3 electrons

• Varies

• Gains 3 electrons

• Gains 2 electrons

• Gains 1 electron

• Does not gain or lose electrons