Intro To Chemistry Ch. 1 Flashcards
What are the two types of materials found on earth?
Mixtures or pure substances.
What is the atomic number?
Number of protons in a given atom.
Who first defined the element and what was the definition?
Empedocles was the first to define the element as a basic substance that all other materials are made from.
How did Robert Boyle define the element?
As a substance that cannot be broken down into simpler materials.
What are compounds?
They are combinations of particular elements.
Who was the first person to break up a compound?
Humphrey Davy
What is the process did Humphrey Davy use to break up a compound?
Electrolysis
Who discovered that the nucleus has a characteristic positive charge and what is it called?
Henry Moseley discovered the atomic number.
What are groups?
Elements that have similar properties and are arranged in vertical columns in the periodic table.
Define a period?
Horizontal row of elements.
What are the elements between groups II and III called?
D-block elements
Who suggested the ‘Law of Triads’
Johan Döbereiner
Name a triad proposed by Döbereiner?
Li, Na, K
What did John Newlands propose?
That properties of elements repeat every 8 elements but this rule only worked for the first 17, named the ‘Law of Octaves’
What did Mendeleev create?
The periodic table
