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All alkali metals are grey in colour with shining surfaces just like other metals. |
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All alkali metals are soft and can cut easily.
Elements |
Density (gcm-3) |
Melting point (℃) |
Boiling point (℃) |
Atomic radius (nm) |
Lithium, Li |
0.534 |
186 |
1609 |
0.133 |
Natrium, Na |
0.970 |
98 |
880 |
0.157 |
Kalium, K |
0.860 |
64 |
760 |
0.203 |
Rubidium, Rb |
1.530 |
39 |
700 |
0.216 |
Saesium, Cs |
1.900 |
29 |
670 |
0.235 |
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All alkali metal conduct heat and electricity. |
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All alkali metals have high melting and boiling point.
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The melting and boiling point are not as high as other metals. |
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The melting and boiling point decrease down the group. This is because as the atomic radius increases, the bonds
between the atoms become weaker. |
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The atomic radius and density of elements increase down the group.
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An increase in the number of filled electron shells will result in increased atomic size, mass and density. |
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The animation below shows the changes in physical properties of Group 1 elements down the group.
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