Answer:
(a) Alkali metals: Francium (Fr)
(b) Chalcogens: Polonium (Po)
(c) Noble gases: Radon (Rn)
(d) Alkaline earth metals: Radium (Ra)
Explanation:
In the periodic table, the atomic mass increases down the group. Therefore, the last element of a group is the heaviest element of the group.
(a) alkali metals: The chemical elements that are present in group 1 of the periodic table, except hydrogen.
<u>The heaviest member of this group is francium (Fr)</u>
(b) chalcogens: The chemical elements that are present in group 16 of the periodic table
<u>The heaviest member of this group is polonium (Po)</u>
(c) noble gases: The chemical elements that are present in group 18 of the periodic table
<u>The heaviest member of this group is radon (Rn)</u>
(d) alkaline earth metals: The chemical elements that are present in group 2 of the periodic table.
<u>The heaviest member of this group is radium (Ra)</u>
Answer:
Explanation: There are 2 moles of C6H12O6 in 300 g C6H12O6 , rounded to one significant figure.
Answer:
The correct options are:
1) Pure chemical substance
2) Element.
Explanation:
each of the term is explained below:
1) <u>Mixture: </u> Since tungsten is an element in periodic table thus it is not a mixture.
2) False by definition of mixture.
3) false by definition of mixture.
4) <u>Solution:</u> Tungsten in a filament is in solid form hence solution is incorrect.
5) Since it is given in the question itself that the sample is pure hence option 'E' is correct as chemical substance is a pure substance that has a homogeneous composition and the sample in the question is given as pure.
6) <u>Compound:</u> By definition of compound it is formed by mixing 2 or more elements but since tungsten is an element that occurs independently in nature hence it is not a compound.
7) Tungsten is a element in the periodic table with atomic number 74.
Answer:
Explanation:
Shifting, labor intensive and monoculture are different in terms of description,restrictions and problem.
Shifting is an agriculture method in which an area if land is cultivated for a while and abandoned for the soil to regain and preserve it's fertility. It is done to restore soul fertility.
It has restrictions because it is done in places where there is large areas of land, if there is not large area of land, it will be done.
It can lead to defforestation because trees are cut fine for land cultivation and after a while the land is abandoned and trees are cut down some where else too.
Labor intensive refers to agricultural industry requiring or needing large amount of labor to produce agricultural products. Labor intensive is restricted to areas where there is low or no people who can engage in agricultural services.
Labor intensive require high skilled people which might not be available.
Monoculture is a farming system where by a single crop is cultivated in an area of land.
The problem of monoculture is that it displaces species and nutrients occuring naturally in an ecosystem.
Monoculture is restricted in areas where diversity of crops are needed.
Isotopes are the same element with a different mass number. They are similar because once again the protons are equal to the atomic number which keeps the identity of the atom the same. But they are different because the masses of each is different.
