Answer is: nitrogen (N) attract electrons most strongly in chemical bonds.
Electronegativity (λ) is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.
λ(C) = 2.55; electronegativity of the carbon.
λ(Ca) = 1.00; electronegativity of the calcium.
λ(N) = 3.05; electronegativity of the nitrogen.
λ(K) = 0.82; electronegativity of the potassium.
The higher the electronegativity, the more the elements attracts electrons.