Questions and Answers
What is an element?
An element is a pure substance that cannot be separated into simpler substances.
Why is an element considered a pure substance?
It is considered pure because it cannot be broken down into any other ingredients.
What are the three categories of elements?
Metals, Nonmetals, Metalloids.
What are the characteristics of metals?
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What are the characteristics of nonmetals?
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What are the characteristics of metalloids?
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How does a group differ from a period on the periodic table?
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What is a compound?
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Can a compound be considered a pure substance?
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How are compounds put together and how are they broken down?
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How do the properties of compounds compare to the elements that make them up?
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Calculate the amount of atoms of each element within the compound Li2O. Li-, O-
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Calculate the amount of atoms of each element within the compound 2 NaOH. Na-, O-, H-___
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Calculate the amount of atoms of each element within the compound Li2(SO4)2. Li-, S-, O-___
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Calculate the amount of atoms of each element within the compound Al(OH)3. Al-, O-, H-___
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Study Notes
Elements
- Elements are pure substances that cannot be separated into simpler substances.
- An element is considered pure as it cannot be broken down into any other ingredients.
Categories of Elements
- Elements are categorized into three groups:
- Metals: Shiny, malleable, ductile, solid, and good conductors of heat and electricity.
- Nonmetals: Dull, brittle, nonmalleable, non-ductile; can exist as gases and are generally poor conductors.
- Metalloids: Exhibit characteristics of both metals and nonmetals and function as semiconductors.
Periodic Table Structure
- The periodic table consists of groups (columns) and periods (rows).
- There are 18 groups and 7 periods on the periodic table.
Compounds
- A compound forms when two or more elements combine chemically.
- Compounds are pure substances made entirely of their own particles, such as water made of water molecules.
Formation and Breakdown of Compounds
- Compounds are formed and separated through chemical processes, such as electrolysis or heat.
- It is not possible to simply pick apart a compound; they cannot be filtered like mixtures.
Properties of Compounds vs. Elements
- When elements combine to form a compound, they undergo a chemical change.
- The resulting compound has different properties than the individual elements that compose it.
Atom Count in Compounds
- For specific compounds:
- Li2O: Lithium (Li) - 2 atoms, Oxygen (O) - 1 atom
- 2 NaOH: Sodium (Na) - 2 atoms, Oxygen (O) - 2 atoms, Hydrogen (H) - 2 atoms
- Li2(SO4)2: Lithium (Li) - 2 atoms, Sulfur (S) - 2 atoms, Oxygen (O) - 8 atoms
- Al(OH)3: Aluminum (Al) - 1 atom, Oxygen (O) - 3 atoms, Hydrogen (H) - 3 atoms
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Description
Test your knowledge on elements and compounds with this Unit 3 review sheet flashcard quiz. Explore key concepts including the definition of an element, why it's considered a pure substance, and the categories of elements. Perfect for students studying chemistry.
