How electronegativity values help to find out the nature of bonding between atoms?

How many electrons are shared in a double bond between two atoms ?

A covalent molecule having a triple bond between its atoms is :

The electronegativity values of atoms A and B are 1.8 and 4.0 respectively. The percentage of covalent character of A-B bond is :

Consider two elements ‘A’ (Atomic number 17) and 'B' (Atomic number 19): (i) Write the positions of these elements in the modern periodic table giving justification. (ii) Write the formula of the compound formed when 'A' combines with 'B.' (iii) Draw the electron dot structure of the compound and state the nature of the bond formed between the two elements.

a ) Human blood has pH value of 7.3 what does it indicate about the nature of the blood b ) what is acid rain what is its pH? How does it effect the aquatic life ?

Using the standard electrode potential , find out the pair between which redox reaction is not feasible . E^(v)"values":Fe^(3+)|Fe^(2+)=+0.77,I_(2)|I^(-)=+0.54,Cu^(2+)|Cu=+0.34,Ag^(+)|Ag=+0.80V