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16 Cards in this Set
- Front
- Back
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What is the periodic table? |
The periodic table arranges elements in a pattern according to their proton numbers. |
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What was a major problem with some of the early periodic tables? |
Early versions failed to take into account of the fact that not all of the elements were known at that time, as: 1) They did not know what atomic number was as they didn't know of subatomic particles. Measured properties (C+P) instead. 2)Could only measure RAM - put in order of.
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Who as the key man who revolutionised the periodic table? In what 2 ways did he? |
Dmitri Mendeleev (1869). 1) In order of RAM, but had to leave gaps in vertical coloumns (groups) for properites to match. 2) Could predict the propeties of undiscovered elements.
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How is an elements place in the periodic table determined? |
By its atomic (proton) number |
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What determines the chemical properties of an atom? |
The number of electrons in the highest energy level. E.G. If the arrangement is 2,8,8,2. It is in group 2 (last number). If its arrangement is 2,8,8,7 it is in group 7 |
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How can we explain trend in reactivity as we go down a group? |
Because of the number of energy levels in the atoms increases. |
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What are the elements in group 1 of the periodic table called? |
The alkali metals |
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When alkali metals react with water they produce ________ and _______ |
Hydrogen + metal hydoxide (dissolve in a solution to give an alkali solution) |
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The reactivity of the alkali metals increases/decreases as we go down the group |
increases |
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What kind of molecules are the halogens? |
diatomic (e.g. They always have a little two after their element. E.g. Cl2, Br2, I2) |
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When halogens form ions, what is their charge? |
1-. Because they have 7 electrons on the outer shell and need 1 more for it to be complete, therefore, they gain an electron. Theyre called halides. |
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What kind of compounds do the halogens form? |
COVALENT compounds. They share electrons with other non-metals. |
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The reactivity of the halogens increases/decreases as you go down the group |
Decreases. Harder to gain an electron the further the shell is from the nucleus. +BP,MP |
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What kind of melting points/density do the transition elements have? |
High MP and high density. |
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What can you say about the conduction of heat an electricity in the transition metals? |
They are very good conductors of heat and electricity. |
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Do the transition metals react vigorously with oxygen or water? |
No. That's the alkali metals. K ignites due to so much heat. |
