chemistry

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  • Created by: 16chlhan
  • Created on: 28-09-20 21:34
what was the first way people arranged the periodic table?
In order of their atomic weight
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who proposed the 'law of octaves'?
Newlands (1864)
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What was the 'law of octaves' ?
it was based of the atomic eight and said that the properties of every eighth element was similar
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why did people disagree with Newlands 'law of octaves'
they said that because people were discovering new elements every day it didn't fit into his table.
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what did Mendeleev do with the periodic table (1869)?
he placed them in the order of atomic weight so that the pattern in their properties could be seen. in some he changed the order so that ones with similar properties were in the same group and let spaces for new elements
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why did scientists except his version if the table?
he used his periodic table to predict the properties f the undiscovered elements and once they were discovered they had similar properties to his predictions
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why do the groups have similar chemical properties?
their outer shells have the same number of electrons
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why are alkali metals stored in oils?
they react with water
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why are elements in group one called Alkali metals?
they form a colourless solution, which when tested with universal indicator turns purple
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to make ionic compounds what do the alkali metals form?
they form positive ions with a charge of +1
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how does the reactivity of alkali metals change down the group?
the reactivity increases going down the group
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what's the name of the group 7 elements?
halogens
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what are the 'halogens'?
they are non- metallic elements. they exist as small molecules made up of pairs of atoms.(covalent bonds)
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what is an example of a covalent bond?
chlorine is a single covalent bond- Cl-Cl.
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why do halogens have low melting and boiling points?
they have weaker intermolecular forces
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what colour is fluorine at room temperature?
pale yellow gas
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what colour is chlorine at rom temperature?
green gas
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what colour is bromine at room temperature?
red-brown liquid
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what colour is iodine at room temperature ?
grey solid which easily vapourises to a violet gas
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what happens to the reactivity f the halogens down the group?
the reactivity decreases
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what can more reactive halogens do?
they can displace a less reactive halogen from an aqueous solution.
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give an example of a more reactive halogen displacing a less reactive halogen?
Cl2 (aq) + 2KI (aq) - 2KCl (aq) +I2 (aq). chlorine + potassium iodide -potassium chloride + iodine
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how can you explain trends in reactivity going down groups in terms of attraction f outer shell and nucleus?
depends on the distance between outer electrons and nucleus, the number of occupied inner shells of electrons ad then the size of the positive charge on the nucleus
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why do metals get more reactive going down the group?
when metals reacts they lose electrons
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why is sodium more reactive than lithium ?
sodium's outer electron is further from the nuclear charge
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where are transition elements found?
in the central block of the periodic table between group 2 and 3
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list ways in which transition metals are different to group 1 elements
transition metals have higher melting points and they're stronger, harder and much more dense
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what don't transition metals react vigorously with?
Water and oxygen
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what does iron react slowly with?
chlorine gas
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Other cards in this set

Card 2

Front

who proposed the 'law of octaves'?

Back

Newlands (1864)

Card 3

Front

What was the 'law of octaves' ?

Back

Preview of the front of card 3

Card 4

Front

why did people disagree with Newlands 'law of octaves'

Back

Preview of the front of card 4

Card 5

Front

what did Mendeleev do with the periodic table (1869)?

Back

Preview of the front of card 5
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