Elements

How many elements are known to exist?

• 4

• 10

• 50

• Over 100

What are some properties of elements?

• Colour, hardness, smell, and taste

• Solubility in water or other liquids

• Density

• All of the things mentioned

What is a compound?

• A mechanical combination of substances involving no change in their character

• A substance that consists of several parts and is formed after a chemical process

• A substance that contains only one kind of atom

• A gas consisting of oxygen and hydrogen

What is the most wide-spread element on Earth?

• Carbon

• Nitrogen

• Oxygen

• Hydrogen

What are the primary building materials of the Universe?

• Mixtures

• Compounds

• Elements

• Gases

The ancient Greeks believed that there were only four elements in nature: fire, air, earth, and water.

• True

• False

Elements are substances that contain only one kind of atom.

• true

• false

When elements combine to form new substances, they always do so in indefinite proportions.

• true

• false

Elements can be solids, liquids, or gases.

• true

• false

The same elements that are common on Earth, such as nitrogen, carbon, and hydrogen, are not common in the Sun and other stars.

• true

• false