Chemical composition Flashcards
What are elements?
Elements are substances that contains only one type of atom. They cannot be broken down into simpler substances.
What are the horizontal rows and vertical columns known as in the Periodic Table?
Periods and Groups respectively.
What is an atom?
The smallest possible unit of a substance that still has its chemical properties and cannot be divided further.
What are molecules?
Multiple atoms combined.
What are the differences between metals and non-metals?
usually shiny; usually dull
good conductors of h&e; poor conductors of h&e
malleable and ductile; brittle
What does malleable mean?
Can be beaten into different shapes.
What does ductile mean?
Can be pulled into different shapes.
What is a compound?
Made up of two or more atoms chemically combined together.
(It may be made up of molecules or ions.)
How are compounds formed?
By a chemical change. A new substance is formed and the process is irreversible.
What are the properties of compounds?
- Elements combined in a fixed proportion by mass
- Pure; fixed melting and boiling points
- Different properties from their constituent elements
- Cannot be separated into their elements by physical methods
What is a mixture?
Made up of two or more elements and/or compounds that are not chemically combined.
Examples of mixtures
Steel, seawater, air
Properties of mixtures
- Have a variable proportion of elements and/or compounds
- Impure; no fixed melting or boiling points
- Elements and/or compounds in a mixture retain their respective properties
- Can be separated by physical methods into their constituent elements and/or compounds
What types of mixtures are there?
Solution and suspension.
What is a solution?
Mixture of two or more substances that are homogeneously mixed, usually dissolved.
