Elements, Compounds and Mixtures

Question 1

What is an element and how do you classify them? Examples? Exists?

Answer 1

A pure substance that cannot be broken down into two or more simpler substances by chemical processes

Metals, Non-metals and metalloids

Calcium, Ca
Carbon, C
Hydrogen, H
Iron, Fe

Atoms or molecules

Question 2

What are metalloids?

Answer 2

Have both metallic and non-metallic properties

Question 3

What are atoms?

Answer 3

The smallest particle of an element that have the chemical properties of that element

Question 4

What are monatomic elements?

Answer 4

Individual atoms

Question 5

What are molecules?

Answer 5

A group of two or more atoms that are chemically combined

Question 6

What are diatomic and polyatomic molecules?

Answer 6

Made up of two atoms

Made up of three or more atoms

Question 7

What is a compound? Examples? Made up of?

Answer 7

A pure substance containing two or more elements that are chemically combined in a fixed ratio

Sodium chloride
Carbon dioxide
Zinc oxide
Calcium carbonate

Molecules or ions

Question 8

What is thermal decomposition and electrolysis?

Answer 8

THERMAL DECOMPOSITION
Involves heating a compound strongly
ELECTROLYSIS
The process of using electricity to break a compound

Question 9

Differences between compounds and mixtures

Answer 9

COMPOUNDS
1. Can only be broken down into its elements by chemical methods
2. Properties of a compound are different from those of its constituent elements
3. A chemical reaction is formed when a compound is formed
4. Occurs at fixed temperature
MIXTURES
1. Components can be separated into by physical methods
2. Properties of a mixture are the same as those of its components
3. No chemical reaction is formed when a mixture is formed
4. Occurs over a range of temperatures