Chemistry unit 1.1 Atoms, elements and compounds Flashcards
1
Q
what are all substances made of?
A
atoms
2
Q
What is an atom?
A
The smallest part of an element that can exist.
3
Q
What are atoms of an elements represented by? Give an example
A
Chemical symbol, E.g Li represents lithium
4
Q
How many elements are in the periodic table?
A
118
5
Q
How are compounds formed?
A
From elements by chemical reactions
6
Q
What is involved in chemical reactions?
A
The formation of one or more new substances and often a detectable energy change.
7
Q
What is an element?
A
A substance made up of the same type of atom
8
Q
What is a compound?
A
Two or more elements chrmically combined in fixed proportions
9
Q
How can compounds be seperated into elements?
A
Only by chemical reactions
