C3) Atoms, Elements, & Compounds Flashcards

1
Q

define an element. [1]

A

made of one type of atom

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2
Q

define a compound [1]

A

made of more than one type of atom chemically bonded together

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3
Q

define a mixture [1]

A

2 or more elements/ compounds mixed together that can be separated by physical means

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4
Q

describe properties of metals [7]

A
  • usually solids at room temp.
  • malleable
  • ductile
  • shiny
  • high melting & boiling point
  • high density
  • good thermal & electrical conductivity
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5
Q

what is the difference between a physical change and a chemical change?

A

physical change = change in state
chemical change = atleast 1 new substance is amde

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6
Q

what is the difference in colour between anhydrous and hydrated forms of copper (II) sulphate?

A

anhydrous copper sulfate = white
hydrated copper sulphate = blue

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7
Q

what is the difference in colour between anhydrous and hydrated forms of cobalt (II) chloride?

A

anhydrous cobalt chloride = blue
hydrated cobalt chloride = pink

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8
Q

what is the mass number of an element?

A

number of nucleons (protons + neutrons)

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9
Q

how are elements arranged in the periodic table?

A

in ascending atomic number

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10
Q

define an isotope

A

atoms of the same element with same number of protons and electrons, but diff number of neutrons

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11
Q

why do isotopes have the same chemical properties?

A

bc they have the same number of electrons in their outer shell

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12
Q

how do metal atoms form ions?

A

lose electrons to form positive ions

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13
Q

how do non-metal atoms form ions?

A

gain electrons to form negative ions

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14
Q

describe an ionic bond

A

the electrostatic attraction between positive metal ions and negative non metal ions

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15
Q

what type of structure do ionic substances form?

A

giant ionic lattices

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16
Q

describe the properties of ionic substances [4]

A
  • low volatility
  • high solubilkity
  • high melting/boiling point
  • conducts when molten / aqueous
17
Q

explain the high melting/boiling point of ionic substances.

A

strong electrostatic forces of attraction between ions that requires a lot of energy to overcome

18
Q

explain the electrical conductivity of ionic substances

A

able to conduct when molten/aquous bc ions are free to move and carry charge

19
Q

describe a covalent bond

A

shared pair of electrons between non-metal ions

20
Q

describe the properties of covalent substances [4]

A
  • high volatility
  • low solubility
  • low melting/boiling point
  • does not conduct electricity
21
Q

explain the low melting/boiling point of covalent substances

A

weak INTERMOLECULAR forces that require a small amount of energy to overcome

22
Q

explain why simple covalent structures dont conduct electricity

A

no free mobile charge carriers to carry charge through the structure

23
Q

name 3 covalent macromolecules

A
  • diamond
    graphite
    silicon oxide
24
Q

describe the structure of diamond [3]

A
  • giant structure
  • made of carbon atoms
  • each carbon forms 4 bonds with another carbon
25
Q

describe the structure of graphite [4]

A
  • giant structure
  • made of carbon atoms
  • each carbon forms 3 bonds with another carbon
  • layered structure
26
Q

describe the structure of silicon oxide [2]

A
  • giant structure
  • one silicon atom for every 2 oxygen atoms
27
Q

explain why diamond, graphite and silicon oxide have a high melting/boiling point [2]

A

lots of strong covalent bonds that require a lot of energy to overcome

28
Q

why can graphite conduct electricity? [3]

A

carbon atoms only form 3 carbon bonds so one valence electron is free and delocalised and can carry charge through the structure

29
Q

explain why graphite is slippery [2]

A
  • weak intermolecular forces between layers
  • can slide off each other
30
Q

what is graphite used for

A

lubricant and a conductor

31
Q

what is diamond used for

A

cutting tools