Is Matter Around Us Pure Test - 7

The most abundant element in earth’s crust is Oxygen. It is present in earth crust in form of oxide, carbonate etc. of metal.
Top 3 most abundant elements in the earth’s crust by mass:
1) Oxygen
2) Silicon
3) Aluminum

The property of metals by which they can be beaten in to thin sheets is called malleability.
The property of metal by which it can be drawn into wires is called ductility.
Gold is most malleable and ductile element.

Hydrogen is the most abundant element in the universe and makes up three-quarters of all matter. Helium is the second most abundant element in the universe and is a major component of main sequence stars such as the Sun. Helium accumulates in the core of stars as a result of hydrogen nuclear fusion. Helium accounts of approximately 27 percent of the Sun's mass.

The element that possesses characteristic of both metal and non-metal are called metalloid. Arsenic is the element that has properties of both metal and non-metal. So Arsenic is metalloid.

Hydrogen sulphide gas is a colorless gas with the characteristic foul odor of rotten eggs. It is very poisonous, corrosive, flammable and acidic in nature.

Mixtures is a substance which consists of two or more pure substances. It has a variable composition. It shows the properties of the constituent substances. Its constituents can be separated by physical methods.

Marie and Pierre Curie discovered the element radium (Ra) on this day in 1898.

It is a substance which consists of two or more pure substances. It has a variable composition. It shows the properties of the constituent substances. Its constituents can be separated by physical methods. E.g.:- sea water, minerals, soil, air, sand and salt, sugar in water, salt in water etc. Mixtures are of two types. They are homogeneous mixture and heterogeneous mixture.A combination of common salt and iron filings is a mixture.

In general metals are in solid state at room temperature, the only metal which is in the liquid state is mercury (Hg).and the only nonmetal that is a liquid at room temperature is bromine.

Cesium is a metal which has very low melting point and change into liquid state above 30°C . Cesium and Gallium  are a liquid slightly above 30°C .