Ordered array implementation of Symbol Table

Question

Ordered array representation with binary search for Symbol table implementation, can be

 char *key[20];
   int val[20];

or

  typedef struct {
        char *key,
         int value
    }Entry;
    Entry array[20];

---

where key is always inserted to maintain ordered array, in either implementation

1)

From insert & search performance perspective, which is the better representation?

2)

Related question about terminology:

From representation aspect, how different are Symbol table, associative array & Dictionary, from each other?