THE PERIODIC TABLETHE PERIODIC TABLE• is arranged in order of increasing number of

protons.

• the atomic numberatomic number of an element is the number of protons in the nucleus and the number of electrons in a neutral atom.

• the atomic weightatomic weight increases with increasing number of protons and neutrons.

• the atomic weight is the average weight of all the isotopes of that element (the average of the natural abundance x mass number).

THE PERIODIC TABLETHE PERIODIC TABLE• is divided into metalsmetals (left side), nonmetalsnonmetals

(right side), and metalliodsmetalliods.• is arranged in rows (across) in order of

increasing energy levels of valence electrons (called periodsperiods). The period number represents the energy level for that row.

• is arranged in columns (down) in order of similar orbitals for the valence electrons (called

groupsgroups).

• The elements are represented by one or two letter symbols, which have some correlation to the element name.

THE PERIODIC TABLETHE PERIODIC TABLEMetals

• Located on the left side of the periodic table

• Tends to lose electrons to form cations

• Has low ionization energies & electronegativity values

• Forms compounds with nonmetals but not other metals

• Good conduction of heat and electricity

• Lustrous & malleable solids excepts Hg which is a liquid

• Ductile

Nonmetals• Located on the right side of

the periodic table• Tends to gain electrons to

form anions• Has high ionization

energies & electronegativity values

• Forms compounds with both metals and nonmetals

• Poor conduction of heat and electricity

• Non-lustrous & brittle or gaseous

• Non-ductile

THE PERIODIC TABLETHE PERIODIC TABLE• is divided into "blocksblocks" which represent the orbital

the electron occupies; s, p, d,s, p, d, and ff.• is read left to right; 1s, 2s, 2p, 3s, 3p, 4s....• is arranged as representativerepresentative elements (ss and pp

block elements), transitiontransition metals (dd block metals), lanthanideslanthanides and actinidesactinides (ff block metals).

• is arranged in order of increasing energy of the subshells; the lowest energy level is always filled first.

• the noble gases are unreactive since they have a completely filled shell and are the lowest in energy.

THE PERIODIC TABLETHE PERIODIC TABLE• Groups or families display similar physical and

chemical reactivity.

• the group number (roman numerals) on top represents the number of valence electrons available for that column.

• common groups are:

group I = alkali metalsalkali metals

group II = alkaline earth metalsalkaline earth metals

group VI = chalogenschalogens

group VII = halogenshalogens

group VIII = noble or inert gasesnoble or inert gases

THE PERIODIC TABLETHE PERIODIC TABLE• demonstrates the trends in atomic

properties; the periodicityperiodicity of the elements. – Atomic radius, Atomic radius,

– ionization energy, ionization energy,

– electronegativity, electronegativity,

– magnetismmagnetism

are some of the properties of atoms which can be predicted using the periodic table.

THE PERIODIC TABLETHE PERIODIC TABLE• Atomic radiusAtomic radius In general, the atomic radii of

the elements within a row (period) decreasesdecreases from left to right due to an increase in nuclear charge whereas the radii increases down a column (group) due to the addition of electrons in higher energy levels.

decreases

increases

THE PERIODIC TABLETHE PERIODIC TABLE• Ionization energyIonization energy This energy is required to This energy is required to

remove an electron from an remove an electron from an atom in the gaseous state. atom in the gaseous state. The first ionization energy is The first ionization energy is the amount of energy the amount of energy required to remove the first required to remove the first electron from an atom as electron from an atom as demonstrated below:demonstrated below:

MM(g)(g) MM(g)(g)++ + + e-e-

increases

decreases

The first ionization energy generally increases across a period and decreases down a group.

THE PERIODIC TABLETHE PERIODIC TABLE• ElectronegativityElectronegativityElectronegativity describes the

ability of an atom to attract electrons to itself in a chemical bond. It is the attractive force that one atom has for a shared pair of electrons of a different atom in a covalent bond. Notice that the electronegativity can be related to the ionization

energy and electron affinity.

increases

decrease

The electro-negativity generally increases across a period and decreases down a group.

THE PERIODIC TABLETHE PERIODIC TABLE• MagnetismMagnetismA Paramagnetic atom is

attracted to a magnetic field because it has one or more unpaired electrons.

A Diamagnetic atom is not attracted to (weakly repelled from) a magnetic field because all of the electrons are paired up.

ParamagneticParamagnetic

LiLi

________ 2s

_________ 1s

DiamagneticDiamagnetic

HeHe

_________ 1s

PRACTICE PROBLEMS about the PERIODIC TABLEPRACTICE PROBLEMS about the PERIODIC TABLE Classify the elements as representative, transition, lanthanide, or actinide.

1. Cd 2. Te 3. Sr 4. Al 5.Gd

6. Rh 7. Cf 8. Be 9. Pd 10. O

Classify the elements by the group name:

1. Be 2. Rb 3. Xe 4. Se 5. Br

Arrange in order of increasing electronegativity.

C O Be N Sr S B

Arrange in order of increasing first ionization energy.

C O Be N Sr S B

Arrange in order of increasing atomic radius.

C O Be N Sr S B

ANSWERS ANSWERS Classify the elements as representative, transition, lanthanide, or actinide.

1. Transition 2. Representative 3. representative 4. representative

5. lanthanide 6. transition 7. actinide 8. representative

9. transition 10. Representative

Classify the elements by the group name:

1. Alkaline earth 2. alkali 3. noble 4. chalogen 5. halogen

Arrange in order of increasing electronegativity.

Sr < Be < B < S = C < N < O

Arrange in order of increasing first ionization energy.

Sr < Be < B < S = C < N < O

Arrange in order of increasing atomic radius.

O < N < C < S < B < Be < Sr

GROUP STUDY PROBLEMSGROUP STUDY PROBLEMSClassify the elements as representative, transition, lanthanide, or actinide.

1. Ca 2. Tb 3. Hg 4. Es 5.Pb

Classify the elements by the group name:

1. Kr 2. I 3. Mg 4. Na 5. O

Arrange in order of increasing electronegativity, first ionization energy, & atomic radius.

Si F In Al Ba

Classify as metal, nonmetal, or metalliod:

1. Kr 2. I 3. Mg 4. Na 5. O

Classify as paramagnetic or diamagnetic:

1. Kr 2. I 3. Mg 4. Na 5. O