Atomic structure and the periodic table 1 Flashcards
Atoms, elements, compounds, and mixtures.
What are all substances made of?
Atoms
What is an atom?
The smallest part of an element that can exist. (and still be identified as that element).
What do chemical symbols represent?
Atoms of each element.
What does the chemical symbol ‘O’ represent?
An atom of oxygen.
What does the chemical symbol ‘Na’ represent?
An atom of sodium.
How many different elements are there?
about 100
Where are elements shown?
The periodic table.
How are compounds formed?
From elements by chemical reactions.
What do chemical reactions always involve?
The formation of one or more new substances.
What do chemical reactions often involve?
A detectable energy change.
What is a compound?
A chemical substance containing two or more elements that are chemically combined in fixed proportions.
How can compounds be separated into elements?
Only by chemical reactions.
How can compounds be represented?
By formulae using the symbols of the atoms from which they were formed.
How can chemical reactions be represented?
-Word equations
-Equations using symbols and formulae
Formula for ammonia
NH₃
Formula for sodium chloride
NaCl
Formula for carbon monoxide
CO
Formula for hydrochloric acid
HCl
Formula for calcium chloride
CaCl₂
Formula for sodium carbonate
Na₂CO₃
Formula for sulfuric acid
H₂SO₄
What are the molecules on the left hand side of an equation called?
Reactants
What are the molecules on the right hand side of an equation called?
Products
You need to be able to write what?
Balanced half equations and ionic equations where appropriate.