World of Chemistry: Chapter 3: Chemical Foundations: Elements, Ions & Atoms

Question 1

John Dalton

Answer 1

Atomic Theory

Question 2

Atomic Theory

Answer 2

A theory established by John Dalton in the early 1800s, used to explain the nature of materials.

Question 3

Compound

Answer 3

A substance made of two or more different elements joined together in a specific way.

Question 4

Robert Boyle 1627-1691

Answer 4

Most significant contribution to science: insistence that science should be firmly grounded in experiments.

Question 5

How many elements did the Greeks suggest that there were & what were they?

Answer 5

Four. Fire, Earth, Water & Air

Question 6

Currently, how many different elements do we know about?

Answer 6

About 115.

Question 7

What is an element symbol?

Answer 7

An element symbol is an abbreviation for chemical elements. Usually consists of the first letter or the first two letters of the elements names. First letter always capitalized and the second is not.

Question 8

What is the law of constant composition?

Answer 8

The law that states that a given compound ALWAYS contains elements in exactly the same proportion by mass.
Example: Water always contains 8g of oxygen for every 1g of hydrogen.