The ionic compounds NaCl and MgS are represented by the diagrams above. Which statement correctly identifies diagram 1 and identifies the compound with the lower melting point, explaining why?
A
Diagram 1 represents NaCl
NaCl
; it has a lower melting point than MgS
MgS
has because the coulombic attractions between the singly charged Na+
Na
+
ions and the Cl−
Cl
−
ions in NaCl
NaCl
are stronger than those between the ions in MgS
MgS
.
B
Diagram 1 represents NaCl; it has a lower melting point than MgS because the coulombic attractions between its singly charged Na+
ions and the Cl−
Cl
−
ions are weaker than those between the ions in MgS
MgS
.
C
Diagram 1 represents MgS
MgS
; it has a lower melting point than NaCl
NaCl
because the coulombic attractions between its doubly charged Mg2+
Mg
2
+
ions and the S2−
S
2
−
ions are stronger than those between the ions in NaCl
NaCl
.
D
Diagram 1 represents MgS
MgS
; it has a lower melting point than NaCl
NaCl
because the coulombic attractions between the doubly charged Mg2+
Mg
2
+
ions and the S2−
S
2
−
ions are weaker than those between the ions in NaCl
NaCl
B
