Reactivity series chart illustrating how different metals react with water and acids, showing their reactivity levels and resulting ions.

Problem Analysis:

The image provided explains the Reactivity Series of metals, which is a ranking of metals based on their reactivity with water and acids. The reactivity series helps predict how metals will behave in chemical reactions, particularly with water and acids. The table in the image shows observations of reactions between different metals and water or acids, along with the ions they form.

The task appears to be about understanding and interpreting the reactivity series based on the given information. Let's break it down step by step.

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Key Points from the Image:

1. Definition of Reactivity Series:
- The most reactive metals react violently with water.
- Metals react with water to form a metal hydroxide and hydrogen gas.
- Observing the reactions of more reactive metals with water helps determine an order of reactivity.
- For less reactive metals, reactions with acids are observed to determine reactivity.
- Reactions with acids are not used for very reactive metals due to safety concerns.

2. Observations of Reactions:
- Water: The table shows how different metals react with water, including the intensity of the reaction (e.g., violent fizzing, no reaction).
- Acid: The table also shows how metals react with acids, noting the intensity and type of reaction.
- Ions Formed: The ions formed by each metal are listed (e.g., K⁺, Na⁺, Li⁺, etc.).

3. Order of Reactivity:
- The metals are listed in decreasing order of reactivity: K, Na, Li, Ca, Mg, Al, Zn, Fe, Sn, Pb, Cu, Hg, Ag, Au.
- More reactive metals are at the top, and less reactive metals are at the bottom.

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Solution Explanation:

#### Step 1: Understanding the Reactivity Series
The reactivity series is a list of metals arranged in order of their reactivity, from most reactive to least reactive. This series helps predict how metals will behave in chemical reactions, especially with water and acids.

#### Step 2: Observations with Water
- K (Potassium): Reacts violently with water, producing a violent fizzing, hydrogen gas, and an alkaline metal hydroxide solution.
- Na (Sodium): Also reacts violently with water, producing explosive results.
- Li (Lithium): Reacts vigorously but less violently than potassium and sodium.
- Ca (Calcium): Reacts with water, producing fizzing, hydrogen gas, and a white precipitate.
- Mg (Magnesium): Reacts slowly with water, producing hydrogen gas and a white precipitate.
- Al (Aluminum): Reacts very slowly with water.
- Zn (Zinc): Does not react significantly with water under normal conditions.

#### Step 3: Observations with Acids
- K, Na, Li: These metals react explosively with acids.
- Ca, Mg, Al, Zn: These metals react with acids to produce hydrogen gas and a salt, but the intensity of the reaction decreases as we move down the series.
- Fe (Iron), Sn (Tin), Pb (Lead): React slowly or not at all with dilute acids.
- Cu (Copper), Hg (Mercury), Ag (Silver), Au (Gold): Do not react with acids.

#### Step 4: Formation of Ions
Each metal forms a specific ion when it reacts. For example:
- K → K⁺
- Na → Na⁺
- Li → Li⁺
- Ca → Ca²⁺
- Mg → Mg²⁺
- Al → Al³⁺
- Zn → Zn²⁺

#### Step 5: Determining Reactivity Order
The reactivity series is determined by observing the intensity and nature of reactions:
1. Most Reactive: Metals like K, Na, Li react violently with water.
2. Moderately Reactive: Metals like Ca, Mg, Al react with water but less intensely.
3. Least Reactive: Metals like Zn, Fe, Sn, Pb, Cu, Hg, Ag, Au do not react with water and require acids to observe any reaction.

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Final Answer:

The reactivity series, based on the observations provided, is as follows:

\[
\boxed{\text{K > Na > Li > Ca > Mg > Al > Zn > Fe > Sn > Pb > Cu > Hg > Ag > Au}}
\]

This series indicates that potassium (K) is the most reactive metal, while gold (Au) is the least reactive. The reactivity decreases as we move from left to right in the series.