Elements, Compounds And Mixtures Flashcards
What are compounds?
2 or more elements that have been chemically joined.
E.g by a chemical reaction
What are elements?
One type of atom
They Cannot be broken down
What is a mixture?
A mixture consists on two or more elements or compounds which are NOT chemically joined. The parts of the mixture behave just the same way as they would if separate.
Difference between compounds and mixtures
~Compounds: new substance produced, Contains 1 substance, different properties, can only be broken down by chemical reactions, fixed composition.
~Mixture: no new substance, contains 2 or more substances, behaves the same, easily separated and not fixed composition.
How many elements are there?
106 known elements but only 92 of these occur naturally-the others artificially made.
How do you classify elements?
Best way: devised and developed as “The Periodic Table Of Elements”
Naming compounds-how do you do it?
Compounds ending in -IDE are result of 2 elements reacting together.
Compounds ending in -ATE usually means that oxygen is present as well as other elements. E.g, copper, sulphur and oxygen: copper sulphate.
What is the periodic table and who invented it?
This system of classifying the elements was developed by Dmitri Mendeleev in 1869.
How is the periodic table set out and used?
All the elements are arranged in order of their ATOMIC NUMBER which is the number of PROTONS that an atom of the element contains.
The vertical columns on the table are called GROUPS, and elements with similar
Properties fall in the same group.
As you go down a group, the properties fall into the same group.
the horizontal lines are called PERIODS and as you go up, change from reactive, to non metals. On extreme right-noble gases.
What are the different groups in the periodic table?
1- Alkali metals
2- Alkaline earth metals
3- The Halogens
4- Noble gases
What is the difference between compounds and it’s elements?
Completely different properties E.g Sodium= dangerous reactive metal Chloride= highly toxic gas When they react, makes sodium chorine-salt
