C1.1 AQA

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  • Created by: Rchilds
  • Created on: 15-05-17 17:27
What are all substances made from?
Atoms
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What is an element?
A substance that contains only one type of atom. Elements can be found in the periodic table.
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What is a compound?
A substance that contains more than one type of atom that are chemically bonded together
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Describe the structure of an atom
A central nucleus containing the protons and neutrons surrounded by electrons orbiting in shells.
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What are the charges on protons, neutrons and electrons?
proton = +1, neutron = 0, electron = -1
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What are the masses of protons, neutrons and electrons?
proton = 1, neutron = 1, electron = 0 (very small so basically 0 compared to protons and neutrons)
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What charge does an atom have and why?
no charge (neutral) because atoms have the same number of protons as electrons so the positive charges perfectly cancel the negative charges
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In the periodic table, when you find an element, what is the bottom number next to it and what does it tell you?
It is the atomic number, it tells you the number of protons (which is the same as the number of electrons)
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In the periodic table, when you find an element, what is the top number next to it and what does it tell you?
It is the mass number, which tells you the number of neutrons + the number of protons (together)
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How do you find the number of neutrons in an element from the periodic table?
Mass number - atomic number
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If an atom becomes charged as it has unequal numbers of protons and electrons (so the charges don't perfectly cancel) what do you call it?
An ion
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How does an atom become a negative ion?
It gains a negative electron (ONLY ELECTRONS MOVE!)
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How does an atom become a positive ion?
It loses a negative electron (ONLY ELECTRONS MOVE!)
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How is the periodic table arranged? (make 3 points)
(1) The elements are arranged in order of their atomic number. (2) They are arranged in columns called groups (3) they are arranged in rows called periods. (in the exam, include the next two cards in your answer, no space here)
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What do the groups of the periodic table show?
Elements in the same group all have the same number of electrons in their OUTER shell, e.g. group 4 has 4 electrons in their outer shell. This means they all behave in a similar way during chemical reactions.
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What do the periods of the periodic table show?
ELements in the same period all have the same number of electron shells (although number of electrons are different)
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What is an electron shell?
It is an electron energy level in the atom
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What is special about group 0 elements?
They have a full outer shell so are very unreactive
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What is a chemical reaction?
When elements exchange or share electrons so they can get a full outer shell (and be stable)
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How are electron shells filled in an atom?
Find out how many electrons the atom has (by looking at the atomic number). Start with the inner most shell and put the electrons in, when the shell is full up, start filling the next shell out.
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What is the maximum number of electrons each electron shell can hold before it's full up?
1st shell = 2 electrons, 2nd shell = 8 electrons, 3rd shell = 8 electrons, 4th shell = 18 electrons
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What happens when a metal reacts with a non-metal?
The metal loses electrons and becomes a positive ion (to get a full outer shell), the non-metal gains these electrons and becomes a negative ion (to get a full outer shell). These then attract each other to form an ionic bond
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How do non-metals bond with each other?
They share electrons so they can get a full outer shell, this is called a covalent bond
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In a chemical formula what do the little number tell you?
How many of each type of atom you have in that compound. YOU CANNOT CHANGE THIS NUMBER WITHOUT CHANGING THE CHEMICAL
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When balancing equations, what do the big numbers tell you?
How many lots of the whole chemical you have e.g. 2MgO means you have 2 lots of MgO so 2 x Mg and 2xO. YOU CAN CHANGE THESE NUMBERS WHEN BALANCING
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What does conservation of mass mean?
No atoms are even created or destroyed in a chemical reaction so total mass of reactants = total mass of products
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How do you balance a chemical equation?
Write a list of the different types of elements ion the reaction. COunt up how many there are of each on the left side and then the right side of the arrow. YOU CAN THEN ONLY ADD BIG NUMBERS. Do this by trial and error to find the right combination
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Other cards in this set

Card 2

Front

What is an element?

Back

A substance that contains only one type of atom. Elements can be found in the periodic table.

Card 3

Front

What is a compound?

Back

Preview of the front of card 3

Card 4

Front

Describe the structure of an atom

Back

Preview of the front of card 4

Card 5

Front

What are the charges on protons, neutrons and electrons?

Back

Preview of the front of card 5
View more cards

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