chem spm development of the periodic table updated

8/8/2019 CHEM SPM Development of the Periodic Table Updated

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JOM KIMIA A1

PERIODIC TABLE OF ELEMENTSA. Historical Development of the Periodic Table

Antoine Lavoisier(1743 1794)

Johann W. Dobereiner(1780 1849)

John Newlands(1837 1898)

Lothar Meyer(1830 1895)

Dimitri Mendeleev(1839 1907)

H. J. G. Mosely(1887 1915)

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Scientist like to find patterns. In the 18th and 19th

centuries, scientist discovered many elements. Theelements found were classified through many stages

of hard work by scientist. This led to the development

of the Periodic Table of Elements that we use today.


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Antoine Lavoisier

Firstchemist who classify the element into 4 group.

The 4 group consisted of gases, metal, non-metaland metal oxide.

Element in the group is classify into metaland non-metal.

Group I Group II Group III Group IV

OxygenNitrogenHidrogenLightHeat

SulphurPhosporusCarbonChlorinFluorin

ArsenicBismutCobaltLeadZincNikel

StanumArgentum

Potassium oxideBarium oxideSilicon(IV) oxsideMagnesium oxideAluminium oxide

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Here is the history ofPeriodic Table of Elements.


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John Newlands

Arranged 62 known elements in order of increasingnucleon number(atomic weights ) in horizontalrows.

He noted that after interval of eight elements similarphysical/chemical properties reappeared.

He was the first to formulate the concept ofperiodicity in the properties of the chemical elements. He proposed the Law of Octaves:

Elements exhibit similar behavior to the eighthelement following it in the table.

He was not successful because;

i. Was only accurate for the first 16 elements(from hydrogen to potassium)

ii. There were no gaps allocated from theelements yet to be discovered.

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Lothar Meyer

Determine the volume of an atom of an element.

Formula;

Volume of an atom

= mass of one mole-atom of the elementDensity of the element

He plotted a graph of volume of atoms of elementsagainst their relative atomic masses to produce

meyers atomic volume curve. From the graph he found elements occupying the

correspondingpositions of the curve exhibit similarchemical properties. example

Li, Na, K, Rb : located at the peak ofthe curve

Be, Mg, Ca, Sr : located after themaximum point

Like Newlands, Meyer showed the properties of theelements recuredperiodically.

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Dimitri Mendeleev

Arranged the elements in order ofincreasing atomicweights and properties.

He left gaps for elements yet to be discovered. He arranged the element that have the same

properties in group.

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Henry Mosely

He was able to derive the relationship between x-rayfrequency and number of protons. and obtained astraight line graph.

When Moseley arranged the elements according toincreasing atomic numbers and not atomicmasses, some of the inconsistencies associatedwith Mendeleev's table were eliminated.

The modern periodic table is based on Moseley'sPeriodic Law (atomic numbers/proton number).

He suggest proton numberdetermine the positionof elements in periodic table.

He arranged elements in periodic table in order ofincreasing proton number.

He also left gaps for the elements yet to bediscovered.

Henry Mosely Periodic Table

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Arrangements of elements in thePeriodic Table

Elements in the Periodic Table are arranged in anincreasing order of proton number.

Elements with similar chemical properties areplaced in the same vertical column.

There are 18 vertical column of elements in thePeriodic Table. Each column is called group. The

vertical columns are known as Group 1 to Group 18. There are 7 horizontal rows of elements in the

Periodic Table. Each of these horizontal rows ofelements is called a period. The horizontal rows areknown as Period 1 to Period 7.

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What is the basic principle applied

in arranging the elements in the

Periodic Table today?


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1. The number of valence electrons in an atom decidesthe position of the group of an element.

The numberof valenceelectron

1 2 3+10 4+10 5+10 6+10 7+10 8+10

Group in

The PeriodicTable

1 2 13 14 15 16 17 18

2. The number of shells occupied with electrons in itsatom decides the period number of an element.

Example 1;

X40

20

Number of proton = 20 Number of electron = 20

Number neutron = 20

Electron arrangement = 2.8.8.2

The number of valence electrons = 2

The number of shells = 4

Group in the Periodic Table = 2Period in the Periodic Table = 4

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Do you know how the electron

arrangement of the atom of an element

related to its group and period?????


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JOM KIMIA A1

Example 2;

Example 3;

Hw: WTO 4.3 pg. 62 no. 1,2,3

Prepared by;Kamal Ariffin B SaaimSmkdblhttp://kemhawk.webs.com

Y

16

8

Number of proton = 8

Number of electron = 8

Number neutron = 8

Electron arrangement = 2.6




Z40

18

Number of proton = 18

Number of electron = 18

Number neutron = 22

Electron arrangement = 2.8.8




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chem spm development of the periodic table updated

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