The activity series shows that ____ is the most reactive and ____ is the least reactive metal.

Explanation

To answer the question about the most and least reactive metals according to the activity series, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Activity Series**: The activity series is a list of metals arranged in order of decreasing reactivity. The most reactive metals are placed at the top, while the least reactive metals are at the bottom.

2. **Identify the Most Reactive Metal**: In the activity series, potassium (K) is the metal that is placed at the top. This indicates that potassium is the most reactive metal.

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