Which of the following will have the highest electronegativity? silicon (si), phosphorus (p) or arsenic (as). explain your
answer

Phosphorus

Explanation:

As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction and electronegativity increases.

As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus electronegativity decreases.

Silicon is present in group 4A and Phosphorus and Arsenic is present in group 5A thus electronegativity of silicon is less than Phosphorus and arsenic. Arsenic is present down to phosphorus thus its electronegativity will less than phosphorus.

P = 2.19

Si = 1.9

As = 2.18