SPM Chemistry Form 4 Notes – Periodic Table of Elements (Part 1) Development of the Periodic Table Periodic Table A) Antoine Lavoisier (1743 – 1794) – French chemist Elements were classified into 4 groups Limitation – some wrong information (light and heat were consider as elements B) Johann Dobereiner (1780 – 1849) – German chemist Elements were classified into groups named as triad (Triad Law – relationship between properties and atomic masses of the elements) Limitation – few elements were classified C) John Newlands (1837 – 1898) – British chemist Elements were arranged horizontally in ascending order of their atomic masses and each row consisted of 7 elements (Law
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
SPM Chemistry Form 4 Notes – Periodic Table of Elements (Part 1)
Development of the Periodic Table
Periodic Table
A) Antoine Lavoisier (1743 – 1794) – French chemist
Elements were classified into 4 groups
Limitation – some wrong information (light and heat were consider as elements
B) Johann Dobereiner (1780 – 1849) – German chemist
Elements were classified into groups named as triad (Triad Law – relationship between
properties and atomic masses of the elements)
Limitation – few elements were classified
C) John Newlands (1837 – 1898) – British chemist
Elements were arranged horizontally in ascending order of their atomic masses and each row
consisted of 7 elements (Law of Octaves – same properties were repeated at every eight
element)
Limitation – obeyed by the first 17 elements only (from H to Ca)
Element Electron arrangement of atomHelium / He 2Neon / Ne 2.8Argon / Ar 2.8.8Krypton / Kr 2.8.18.8Xenon / Xe 2.8.18.18.8Radon / Rn 2.8.18.32.18.8
Physical properties
Monoatomic gases
Colourless gas at room temperature
Insoluble in water
Cannot conduct electricity
Poor conductors of heat
Melting point and boiling point increases (going down the group) – atomic size increases and
force of attraction between atoms of each element become stronger
Density of element increases (going down the group)
Chemical properties
Chemically inert / not reactive / non-flammable – do not gain, lose or share electrons with
other elements
Uses
Helium – airships, weather balloons, cool down metals
Neon – advertising light bulb
Argon – welding, filled light bulbs
Krypton – used in laser, filled photographic flash lamps
Radon – treat cancer
SPM Chemistry Form 4 Notes – Periodic Table of Elements (Part 3)
Alkali metal atom arrangement
Group 1 elements
Group 1 elements are known as alkali metals
Atomic radius (atomic size) – increases (going down the group)
The outermost shell of the atoms (Li, Na, K, Rb, Cs and Fr) have 1 valence electron
Good reducing agents
Very reactive – increases (going down the group)
Very electropositive – increases (going down the group)Element Electron arrangement of atomLithium / Li 2.1Sodium / Na 2.8.1Potassium / K 2.8.8.1Rubidium / Rb 2.8.18.8.1Caesium / Cs 2.8.18.18.8.1Francium / Fr 2.8.18.32.18.8.1
Physical properties
Grey solids with shiny silvery surfaces when freshly cut
Soft solids at room temperature
Good conductors of electricity
Good conductors of heat
Low melting point and boiling point (compared to heavy metal)
Na, Mg (metals): form oxides with basic properties
Al (metal): form oxides with both basic and acidic properties = amphoteric
oxides
Si (semi-metal): forms oxides with acidic properties
P, S, Cl (non-metals): forms oxides with acidic properties
Uses of semi-metals (metalloids)
Semiconductor (flow in one direction)
Microchip
SPM Chemistry Form 4 Notes – Periodic Table of Elements (Part 6 – Final)
Transition elements
Elements from Group 3 to Group 12
Metals
Atomic radius (atomic size) approximately the same
Solids with shiny surfaces
Very hard (compared to Group 1 and Group 2 metals)
High density
Ductile (ability to stretched into wires without breaking)
Malleable (ability to be bent into new shape)
High tensile strength (ability to stay in their shape without breaking)
High melting and boiling points
High density
Good conductors of electricity
Good conductors of heat
Electronegativity is low but increases (across the series)3 4 5 6 7 8 9 10 11 12Sc Ti V Cr Mn Fe Co Ni Cu ZnY Zr Nb Mo Tc Ru Rh Pd Ag CdLa Hf Ta W Re Os Ir Pt Au HgAc Rf Db Sg Bh Hs Mt Ds Rg Uub
Colourful Complex of Transition Elements
Special characteristics
Form coloured ions (Cu2+: blue / Fe2+: pale green / Fe3+: yellow)
Form coloured compound (cobalt chloride crystal: pink)
Different oxidation numbers in their compound
Useful catalysts (nickel – hydrogenation of vegetable oil, copper(II)
sulphate – reaction of zinc with dilute sulphuric acid to liberate hydrogen
gas, manganese(IV) oxide – decomposition of hydrogen peroxide to liberate
oxygen gas, iron – Haber process,vanadium(V) oxide – Contact
process, platinum – Ostwald process)
Form complex ions (bigger-sized polyatomic ion) (Hexacyanoferrate(III) ion /
[Fe(CN)6]3- )
Uses
Iron – used as steel
Chromium – coating corroded metals, heat-resisting alloys and make stainless
steel
Copper – making cables, pipes and electrical wires
Titanium – metal pipes and tanks, wings of supersonic aircraft