Step-by-step explanation:
We have to predict the type of bond that a pair of atoms would form. To do that we can compare the electronegativities of the elements. A large difference between their electronegativities will result in an ionic bond (one of the atoms will tend to gain the electrons and the other one to lose them) and if the difference is small they will tend to form a covalent bond (they will share the electrons.
So, we have to look for the electronegativity of each element and then sustract them. If the difference between them is greater than 1.7 the bond will be ionic and if the difference between is smaller than 1.7 the bond will be covalent.
a) Zinc and zinc:
Electronegativity of Zn = 1.65
ΔE = Electronegativy of Zn - Electronegativity of Zn
ΔE = 1.65 - 1.65
ΔE = 0 ----> it is smaller than 1.7 so it is covalent
b) Oxygen and nitrogen:
Electronegativity of O = 3.44
Electronegativity of N = 3.04
ΔE = Electronegativy of O - Electronegativity of N
ΔE = 3.44 - 3.04
ΔE = 0.4 ----> 0.4 is smaller than 1.7 so it is covalent
c) Phosphorous and oxygen:
Electronegativity of O = 3.44
Electronegativity of P = 2.19
ΔE = Electronegativy of O - Electronegativity of P
ΔE = 3.44 - 2.19
ΔE = 1.25 ----> 1.25 is smaller than 1.7 so it is covalent
d) Magnesium and chlorine:
Electronegativity of Cl = 3.16
Electronegativity of Mg = 1.31
ΔE = Electronegativy of Cl - Electronegativity of Mg
ΔE = 3.16 - 1.31
ΔE = 1.85 ----> 1.85 is greater than 1.7 so it is ionic.
Answer:
a) Zinc and zinc = covalent.
b) Oxygen and nitrogen = covalent
c) Phosphorous and oxygen = covalent
d) Magnesium and chlorine = ionic