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Lesson 3.7 ENH Why do we care about Ions?

Last updated 7 months ago
21 questions
Untitled Section 1
The atoms in many solids are ions. Positive and negative ions are attracted to each other. The attraction is so strong that substances made of ions tend to be solids at room temperatures. Ever tried to crush a rock? Its made mostly of ions. Crystals are a special form of a solid because the pattern that the ions is arranged is consistent throughout the substance.

Crystalline solids often form after substances are dissolved in water.

What is happening in the video?
The solid contains positively charged sodium ions and negatively charged acetate ions. Dissolving the solid in water separates the ions.

The picture below shows how a sodium chloride (table salt) crystal dissolves. The water molecules surround the ions forming layers that separate them.


If the separated ions can find each other and come back to together then crystallization happens. Crystallization is the process of forming a solid from the separated ions. Normally to grow crystals, we remove water through evaporation. This removes the layers of water between the ions and makes it more likely that the positive and negative ions can find each other.

Many rocks and minerals form through crystallization deep in the earth. Magma- the liquid rock found under the crust of the earth- is so hot that many of the ions that normally form rocks and minerals are separated. When magma cools, the ions come together and form crystals. The beautiful patterns of many of the rocks in the classroom are formed when positively charged metal ions pair up with negatively charged ions. As the rock cools, new compounds formed of positive and negative ions are formed and crystals like quartz are formed. Quartz it typically clear or white. Check out the samples in the classroom.


Magma can also be exposed to hot water as it travels through the crust. Ions from the magma travel into the hot water and a second cycle of crystallization often happens leading to the formation of new compounds in side the quartz. Many of these compounds contain transition metal ions so they are brightly colored.
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What process happens when separated ions find each other and come back together to reform a solid?

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What happens when a sodium chloride crystal dissolves in water?

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Many substance are solid at room temperature because

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How can we normally grow crystals in a controlled environment?

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What causes the beautiful patterns in many of the rocks in the classroom.

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What happens when magma cools?

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Check out the rock collection in the classroom. Pick out a rock that you think contains ionic compounds and describe it. Be sure to explain why you think the ionic compounds are there.

Sorting Ions to Identify Elements in a Substance
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What is the first step to identify substances in a crime scene sample?

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Why do negatively charged ions move towards the positively charged plate?

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What is the charge of ions for most metallic elements?

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How can noble gases be separated from metals and nonmetals in a device that sorts ions?

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Which path would a cobalt (II) ion (Co²⁺) follow in the ion sorter?

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Which path would a oxide ion ( O²⁻) follow in the ion sorter?

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Which path would a neutral neon atom follow in the ion sorter?

Required
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An ion sorter like the one discussed above can be used to separate

Electrolytes
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What are the main ingredients in sports drinks?

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What elements in sports drinks are considered electrolytes?

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What is the main sweetener in low-calorie drinks?

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How do stimulants in energy drinks act as diuretics affect the body?

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Why are energy drinks not recommended for young people?

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Why are electrolytes in sports drinks important for our bodies during physical activities?