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15 Cards in this Set
- Front
- Back
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All atoms contain...
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protons, neutrons and electrons
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How are protons, neutrons and electrons charged?
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Protons- positively
Neutrons- no charge Electrons negative |
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Describe protons and neutrons
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Protons and neutrons are the Heavy particles in an atom. They have a mass of one atomic mass unit and they are found in nucleus.
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Describe electrons
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They have tiny mass
They orbit the nucleus in shells. 1st shell holds 2 electrons 2nd and 3rd hold 8 electrons. |
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What is the ATOMIC NUMBER?
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The number of protons (which equals the number of electrons)
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What is the MASS NUMBER?
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Number of protons+ number of neutons
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What are isotopes?
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They are atoms with same number of protons, but with different number of protons.
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Group 1
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The alkali metals
Soft metals stored under oil Low densities Low melting points Tarnish in air Most reactive group of metals Get more reactive as you go down the group |
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Group 2
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The alkaline earth metals
Higher melting points and densities tha group 1 Less reactve than group 1 Get more reactive as you go down the group |
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Transition metals
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Hard and dense
High melting points Less reactive than group 1 and 2 Form coloured compounds Can form comound with more than one formula Are important catalysts in industry |
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Magnetic metals
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Iron, cobalt and nickel
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Group 7
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Are called halogens
Exist as diatomic molecules Reactive group of non-metals Get less reactive as you go down the group |
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Group 8 or 0
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Called nobel gases
Exist as single atoms Very unreactive Full outer shell |
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Group number
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Elements group number equals the number of electrons on the outer shell
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Reactivity series
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Lists metals in order of reactivity
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