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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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.
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What process happens when separated ions find each other and come back together to reform a solid?
Evaporation
Condensation
Sublimation
Crystallization
What happens when a sodium chloride crystal dissolves in water?
Ions disappear
Water molecules repel the ions
Water combines with sodium chloride
Water molecules surround ions, separating them
Many substance are solid at room temperature because
they contain only positive ions
they contain only negative ions
the contain both positive and negative ions
How can we normally grow crystals in a controlled environment?
Removing water through evaporation
Adding more ions
Increasing the temperature
Increasing the pressure
What causes the beautiful patterns in many of the rocks in the classroom.
Artificial coloring
Surface erosion
Formation of new compounds when ions pair up
Pressure and heat only
What happens when magma cools?
Separation of ions in the magma
No change
Formation of crystals like quartz
Formation of water molecules
What is the first step to identify substances in a crime scene sample?
Sorting ions
Identifying elements
Identifying particles
Identifying isotopes
Why do negatively charged ions move towards the positively charged plate?
Because of electrical attraction
They are smaller
Because of magnetic attraction
They are lighter
What is the charge of ions for most metallic elements?
Negative
Alternates between positive and negative
Positive
Neutral
How can noble gases be separated from metals and nonmetals in a device that sorts ions?
They are always neutral and fly straight through
They are always positive and move to negative plate
They are always negative and move to positive plate
They alternately move to positive and negative plates
Which path would a cobalt (II) ion (Co²⁺) follow in the ion sorter?
Which path would a oxide ion ( O²⁻) follow in the ion sorter?
Which path would a neutral neon atom follow in the ion sorter?
An ion sorter like the one discussed above can be used to separate
fluorine gas from chlorine gas
sodium from magnesium in salts from a lake bed
carbon atoms from the iron atoms in steel
xenon from rocks made of silicon and oxygen
What are the main ingredients in sports drinks?
Water, Aspartame, Acesulfame Potassium, Sodium
Water, Sugar, Salt, Sodium and Potassium
Sucrose, Glucose, Fructose, Salt
Caffeine, Guarana, Sugar, Taurine
What elements in sports drinks are considered electrolytes?
Flavorings and colors
Sodium (Na+) and Potassium (K+)
Sugar
Water
What is the main sweetener in low-calorie drinks?
Table sugar
Caffeine
Sucralose, Acesulfame Potassium or Aspartame
Taurine
How do stimulants in energy drinks act as diuretics affect the body?
Slow water absorption
Increase energy levels
Increase blood pressure
Encourage excretion of water
Why are energy drinks not recommended for young people?
Contains stimulants that act as diuretics
Decomposes into harmful chemicals
Contains high levels of sodium
Cause dehydration due to high sugar levels
Why are electrolytes in sports drinks important for our bodies during physical activities?
