The Periodic Table!!!!The Periodic Table!!!!

3.1 The Periodic Table

• History• Organization• Electron arrangement & valence energy

level

Dmitri Mendeleev

• 1834-1907; sequenced known elements in order of increasing atomic mass

• Elements with similar properties in same column.

• Called Periodic Table because it highlighted the repeated (periodic) patterns of properties.

Periodic Law

• Chemical & physical properties of the elements repeat in a regular, periodic pattern when arranged by atomic number

• This is the basis for the modern periodic table – arranged by atomic number.

The Modern Periodic Table

• Using the information in your data booklet, complete the periodic table worksheet.

• Be sure to include a legend on your worksheet.

Alkali metals (not H) Alkaline earth metals

Transition metals Halogens Noble gases Inner transition Inner transition

G GGG

GG

G GGG

GG

L

L

VIIAVIAVAIVAIIIAIIAVIIAIA

Metalloids

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• Group Names:– Two systems: Old & New

• Old: Roman numerals with either A or B• New: Integers 1-18 from left to right• Group VA = Group 15

• Alkali Metals: – Group 1– Soft, light, reactive metals

• Alkaline Earth Metals: – Group 2– Harder, denser, and stronger than alkali metals

• Transition Metals: – Group 3-12– Form positive ions, reactive, make coloured

compounds

• Metalloids: – On staircase between metals and non-metals– Exhibits properties of both

• Halogens: – Group 17; Reactive non-metals– Electron deficient and readily share electrons

with other elements

• Noble Gases:– Group 18– Do not react chemically with other materials

and cannot be absorbed– Valence shell full

The Periodic Table & Electrons• Periodic trends are linked to the way electrons

fill energy levels.

• Remember that for each proton there is one electron in an atom, therefore as the atomic number increases, so does the number of electrons.

• To understand trends, we use the Bohr-Rutherford Model of the atom.

The Bohr-Rutherford Model

• Electrons in energy levels• 2 in first level• 8 in other levels

• What element is this?• Sodium, Na

• Group Related Pattern:

– All the elements in a group have the same number of valence electrons.

– The old number system – The roman numeral is the same as the number of valence electrons.

– The new system – The last digit of the number is the number of valence electrons.

• Period-Related Pattern

Period Number = Number of Energy Levels

3.2 Physical Properties

• Ionization energy• Electronegativity• Atomic Radii • Ionic Radii

• Across period 3 & down group 1 & 17

More Trends – Worksheet• Ionization Energy: The energy required to

remove one valence electron from an atom.

• Electronegativity: How strongly an atom attracts the electrons in a covalent bond

• Atomic Radius:The distance from the nucleus to the valence electron shell of an atom

• Ionic Radius: The distance from the nucleus to the valence electron shell of an ion

Ionization energy vs. atomic numberIonization energy vs. atomic number

CaK

H

He

Li

BBe C

N O

F

Ne

Na

MgAl

SiP S

Cl

Ar

0

500

1000

1500

2000

2500

0 2 4 6 8 10 12 14 16 18 20

Element

Ioni

zatio

n en

ergy

(kJ/

mol

)

Ionization Energy Trend

Electronegativity Trend

Atomic radius vs. atomic numberAtomic radius vs. atomic number

Ca

K

H He

Li

BBe

C N O FNe

NaMg

Al Si P S ClAr

0

50

100

150

200

250

0 2 4 6 8 10 12 14 16 18 20

Element

Atom

ic R

adiu

s (p

m)

Atomic Radius & Ionic Radius

http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/atomic4.swf

Ionic Radius Trend

3.3 Chemical Properties• Group Properties:

– Alkali metals with water– Alkali metals with halogens– Halogens with water– Halogens with halide ions

• Oxides of period 3 properties– Ionic vs. covalent bonding nature– Basic vs. acidic nature– Industrial processes

Alkali metals with H2O

• M + H2O MOH + H2

• Trend:Very reactive; increasing down group• Observations:

– Highly exothermic – heat & light– Fizzing of hydrogen gas formed

– Video

Alkali Metals with Halogens

• M + X2 MX• React in 1:1 ratio

Halogens with H2O

• Reactivity decreases down group because electronegativity and oxidizing power decreases down group; electrons farther from nucleus and are shielded

• Halogens General Video

Halogen and halide ions

Higher Halogen displaces lower halogen from salt; never other way around!

•Cl2 + I- Cl- + I2

•Cl2 + Br- Cl- + Br2

•Br2 + I- Br- + I2

•Br2 + Cl- No rxn

•I2 + Cl- No rxn

•I2 + Br- No rxn

Halogen and metal

• Make salts with halide ion• Salts are usually white in colour and soluble

in water creating colourless solutions• Common insoluble halides: silver and lead

Things to Know:• Ionic compound– attraction of ions creates bond• Covalent compound – shared electrons create

bond• Polar Covalent – a covalent bond where

electrons are not shared equally creating positive and negative “ends” on the bond

• Acidic – having a pH of less than 7; H+• Basic – having a pH of more than 7; OH

Oxides:

• Compounds containing at least one oxygen atom

• Bonded with metal: ionic compound & basic• Bonded with non-metal: polar covalent

compound; polarity decreasing across period & acidic (increasing across period)

• **aluminum oxide is amphoteric – reacts with acid and base**

Oxide + H2O Reactions• Na2O(s) + H2O(l) 2Na+

(aq)+ 2OH-(aq)

• MgO + H2O → Mg(OH)2

• P4O10(s) + 6H2O(l) 4H+(aq) + 4H2PO4-

(aq)

• SO3(s) + H2O H+(aq) + HSO4-

(aq)

Another MgO rxn: MgO(s) + 2HCl(aq) Mg2+

(aq) + 2Cl-(aq)