Question

How would you arrange these elements in order of decreasing electronegativity: N, Al, Na, P ?

Answer 1

Electronegativity is defined as the tendency of the atom in the molecule to attract the shared pair of electrons towards itself. This property is dimensionless as it is only a tendency. We measure the electronegativity on several scales but most common is the Pauling scale.

Complete answer:
The electronegativity of the element is the tendency which is used for estimating the ability of the atom so that the formation of negative ions takes place by attracting electrons towards it. The electronegativity for metals is lesser than that of non metals. This is so because the non metallic character of the elements tends to increase so the electronegativity increases. So the elements given to us are N,Na,Al and P. Out of them N belongs to period 2 while other belongs to period 3. So the electronegativity for nitrogen will be more than the others. While among sodium , aluminium and phosphorus the least will be for sodium and the highest would be of phosphorus as electronegativity increases across the period. Electronegativity is considered as the function of the unshielded nuclear charge and it is also the ability of the atom which is involved in the chemical bond for polarising the electron density towards itself. So the order will be
$N > P > Al > Na$

Note: The electronegativity is used in determining the non metallic as well as the metallic character of the element. It also helps in the determination of the polar as well as the non polar bonds in the molecules. The fluorine is the most electronegative element while the cesium is the least electronegative element.