atoms,elements and compounds. Flashcards
(17 cards)
What doe chemical reactions involve?
- measurable energy change
- compounds are broken or formed
- no atoms are created or destroyed
- at least 1 new substance is created
what is an element
an element is a substance that contains only one type of atom
what are atoms
atoms are the smallest part of an element that can exist
what is a compound
a compound contains two or more elements which are chemically combined in fixed proportions
scientist use chemical formulae to show…
- the different elements in a compound
- how many atoms of each element one molecule of the compound contains
how can compounds be separated into their component elements?
chemical reactions or electrolysis
what rules apply when naming a compound with 2 elements?
usually metal and non metal
- the metal name does not change
- the non-metals name ends in ice.
What rules apply when naming a compound with a metal that reacts with ions that consists of two or more non metal atoms covalently boded
- the metal name does no change
- the non metals name ends in are if oxygen is present
how do scientist name compounds that contain a transition metal?
names become more complicated so to distinguish them, roman numerals indicate the charge on the metal ion
why does the mass of products equal the mass of reactants
no atoms are lost or made
what do chemical equations show
reactants and products
What are the different state symbols and why do we add them?
s = solid l = liquid g = gas aq = aqueous (dissolved in water)
we add them to show the state of the reactants/products
why is it useful to have symbols for atoms of different elements?
when elements join together to form a compound, it tells you how many atoms there are.
what is the difference between an element and a compound?
elements contain one type of atom
compounds contain more than one type
explain why it is difficult to separate a compound , compared to an element.
Elements in a compound are chemically joined together
what does it mean if a compound ends in -ide?
contains 2 elements; usually metal and non metal
what does it mean if a compound ends in -ate?
contains 3 or more elements , 1 of which is ALWAYS oxygen
