Which of the following pairs represent isotopes and which represent isobars?
`""_(19)^(40)K, ""_(20 )^(40)Ca`
Calculate the difference in the number of neutrons in the isotopic pairs.

Explanation

To determine whether the given pairs represent isotopes or isobars, and to calculate the difference in the number of neutrons, follow these steps:

### Step 1: Identify the atomic numbers and mass numbers
The given pairs are:
- Potassium (K): \( _{19}^{40}K \)
- Calcium (Ca): \( _{20}^{40}Ca \)

Here, the atomic number (Z) is the subscript, and the mass number (A) is the superscript.
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