Melting and boiling point and their periodic trends:

 Melting and boiling point:

(A) Melting point: The temperature at which  a solid material changes into the liquid material is called melting point and process is called melting.

(B) Boiling point the temperature at a liquid material changes into its vapour is called boiling point and the process is called boiling. 

(C) Lower atomic volume generally leads to higher density, increases hardness and brittleness, less malleability and ductility.

(D) Trends in groups: 

1- When we move top to bottom in group of S-Block, the melting point and boiling point decrease.

2- When we move top to bottom in all group of d-Block, the melting point and boiling point increases.

 3- While we move IIIA TO VIA Groups, the MP and BP decreases.

 4- While we move VA TO VIIA Groups, the MP and BP increases.

(E) Trends in period: 

When we move from left to right through periodic table the value of MP and BP first increases to maximum after decrease like density.

Related Questions:

(1) What are the Amphoteric metals ? gives Examples.

(2) Name of total metalloids present in periodic table ?

(3) Total numbers of elements which are liquid at normal temperature is ?

(4) What is Mendeleev's periodic table ? give important features and draw back of Mendeleev's table.

(5) What is atomic density ? give the periodicity of atomic density in periods and groups.

(6) Why there are 2, 8 and 8 elements in first, second and third periodic of periods table respectively ? Explain.

(7) In alkali metal group which is the strongest reducing agent in aqueous solution and why?

(8) The electron affinity of sulphur is greater than oxygen. Why?

(9) The first ionization energy of carbon atom is greater than that of boron atom, whereas reverse is true for the second ionization energy. Explain.

(10) The electronegativities of B, Al, Ga are 2.0, 1.5, 1.6 respectively. The trend is not regular. Explain.

(11) Li2CO3 decomposes on heating but other alkali metal carbonates don’t. Explain.

(12) Of all noble metals, gold has got a relatively high electron affinity. Explain.

(13) Ionization energy of Boron is smaller than Beryllium even though effective nuclear charge is higher?

(14) What are the increasing order of ioni radii of first group elements in water ?

(15) What are the increasing order of molar conductivity of first group elements in water ?