Answer:
In Dobereiner’s triads, elements were placed :
- According to increasing order of their atomic masses.
- Into groups which have similar chemical and physical properties.
- In each group there were three elements.
In Modern periodic table, elements are placed:
- According to increasing order of their atomic numbers.
- Into groups and these groups are assigned according to the numbers of valence electrons present in their valence shell.
Aspects of Dobereiner’s triads agreed with the modern periodic table
- Element of the same group will have similar chemical and physical properties.
Disagreement with the modern periodic table.
- Not all groups obeyed law of triads.
- On the basis of properties all known elements could not be classified into groups of triads.
Answer: Option (c) is the correct answer.
Explanation:
Polar molecules are defined as the molecules that chemically combine together and have partial opposite charges.
For example, 
is a polar molecule as due to the difference in electronegativity of hydrogen and oxygen atom there is partial positive charge on hydrogen atom and partial negative charge on oxygen atom.
On the other hand, molecules which are neutral in nature are known as non-polar molecules. A non-polar molecule is formed by equal sharing of electrons.
For example, 
is a non-polar molecule.
As in a large polar molecule, there will be greater force of attraction between the oppositely charged ions due to large surface area. Hence, large amount of heat needs to given in order to break the bonds.
Therefore, we can conclude that a large polar molecule will have the highest boiling point.
Answer:
Volume
Explanation:
Cubic centimeters are used to measure the space an object takes up, or its volume.
A, the protons and neutrons are heavier than electrons. The electrons orbit the nucleus, and have negligible mass.
