Symbols, formulae and equations Flashcards
Element definition
It is a substance that consists of only one type of atom and cannot be broken down into anything simpler by chemical means
Compound definiton
It is a substance that consists of two or more (different) elements chemically combined
Diatomic molecule definition
Two atoms covalently bonded in a molecule
Examples of diatomic molecules
Hydrogen, nitrogen, oxygen, fluorine, chloride, bromine and iodine
What does a chemical formula tell us?
The name of elements present and the number of each type of atom present
Valency definiton
The combining power of an atom or ion. The number of electrons a metal has to give away from its outer shell or a non-metal need to gain to complete its outer shell.
Way of working out fromulaes?
Swap and drop
How to know the valency of an ion?
Its charge is its valncey
What’s the rule to naming compounds?
Only use ate or ite if there is oxygen present
What are the state symbols?
(S) = solid
(l) = liquid
(g) = gas
(aq) = aqueous solution (dissolved in water)
How to balance equations?
Make sure there are an even number of atoms on each side of the equation
What is an ionic equation?
It is a chemical equation in which species are written out as their dissociated ions. E.g. instead of NaCl it’s written as Na+ and Cl-
What is the ionic equation for neutralisation?
H+ + OH- = H2O
