Which is the hardest non-metal?
Diamond is the hardest natural substance on Earth, but it is also very brittle and will shatter if hit with a hammer. Graphite is unusual because it is a non-metal that conducts electricity….Diamond and graphite.
| Diamond | Graphite |
|---|---|
| Transparent and colourless | Opaque and black |
| Hard | Soft |
Which non-metal is lustrous and shiny?
Iodine
Which is the softest non metal?
As oxygen and bromine are not solids so being soft or hard is not applicable to them hence the softest solid non-metal from them is option C, sulphur.
Which non metal is shiny?
Graphite is the most stable form of carbon and so it is used as the standard state for defining the heat and formation of carbon compounds. It has a layered planar structure and the bonding between the layers is vander waals bonds. It is a non metal with shining surface.
Which non metal is lustrous in Colour?
Iodine and graphite are lustrous, coloured as well as a non metal.
Which metal is preserved in kerosene?
Metal which are preserved in kerosene – Sodium, Lithium and Potassium. Lustrous coloured non-metal – Iodine and Diamond . They have a slight metallic lustre. Metal which can melt while kept on palm are – Gallium & Caesium.
Is preserved in kerosene?
Answer. (a) Sodium, lithium & Potassium are preserved in kerosene.
Which metal is kept in wax?
Lithium is kept wrapped in paraffin wax because unlike sodium or potassium it can’t be stored in kerosone oil as, then it floats to the surface due to its very low density.
Why is lithium metal stored in kerosene?
Lithium metal because of low density is a light metal and therefore floats on the surface of the kerosene oil. To prevent its contact with air, it is kept wrapped in paraffin wax.
Why is lithium kept under kerosene?
Lithium cannot be stored in kerosene oil , because it is the lightest metal and it floats on its surface and react with air . Therefore it is kept wrapped in paraffin wax. Except Be and Mg , all other s – block metals impart color to the flame due their low ionization potential.
Why potassium or sodium are not stored under water?
While, Na and K are soft metals which are highly reactive with water and catches fire even with moisture and so they are kept in kerosine which prevents water to reach to the metals.
Why is gold silver and platinum used to make Jewellery?
Platinum, gold and silver are used to make jewellery because the metals used in jewellery are always be chosen on the basis of its reactivity. They are highly lustrous metals which are resistant to corrosion. They are highly malleable and ductile so can be transformed into any shape or design.
How does the reaction of potassium and sodium with cold water differ explain?
Metals at the top of the reactivity series (Sodium, potassium) react readily (violently) with cold water forming hydroxides with the liberation of H2, the heat evolved is sufficient for the hydrogen to catch fire. While metals like Magnesium is less reactive towards cold water. It reacts very slowly with cold water.
Why is potassium more reactive than sodium in water?
As potassium is larger than sodium, potassium’s valence electron is at a greater distance from the attractive nucleus and is so removed more easily than sodium’s valence electron. As it is removed more easily, it requires less energy, and can be said to be more reactive.
Which is more reactive with water sodium or potassium?
In this dramatic demonstration, lithium, sodium, and potassium react with water to produce hydrogen gas and the hydroxides of the metals. Lithium reacts fairly slowly, fizzing….Alkali Metal Reactivity.
| Element | First Ionization Energy (kJ/mol) |
|---|---|
| Li | 520 |
| Na | 496 |
| K | 419 |
Why does potassium react with cold water?
(a) Potassium (K) reacts with cold water to form potassium hydroxide and hydrogen gas.