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Chemistry GCSE > Chemistry Atomic structure, Covalent bonding and Metallic bonding half term test > Flashcards

Chemistry Atomic structure, Covalent bonding and Metallic bonding half term test Flashcards

1
Q

What’s the order of the development of the atomic models?

A
  • Greeks said that atoms are tiny spheres that cannot be divided
  • Plum pudding model, a ball of positive charge with electrons embedded in it
  • Alpha particle scattering experiment, showed that the mass of an atom is concentrated at the centre and the nucleus is charged
  • Positively charged nucleus orbited by electrons like planets around the sun
  • Niels Bohr adopted the nuclear model by suggesting that the electrons orbit at specific distances
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2
Q

Definition of atom

A

Smallest part of an element that can exist

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3
Q

Definition of element

A

Contains only one type of atom

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4
Q

Definition of compound

A

consists of two or more elements or compounds that are chemically combined

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5
Q

How to calculate relative atomic mass

A

Total mass of atoms/ total number of atoms

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6
Q

What are isotopes?

A

atoms of the same element but with different numbers of neutrons therefore different masses.

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7
Q

Who discovered the neutron?

A

James Chadwick

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8
Q

What is covalent bonding?

A

When atoms share pairs of electrons. (strong bond)

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9
Q

Advantages of displayed formula

A
  • quick and easy to draw and identify
  • shows how they are bonded to each other
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10
Q

Advantages of ball and stick models

A
  • shows the shape of the molecule
  • 3D
  • shows which atoms are bonded to which
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11
Q

Advantages of dot and cross diagrams

A
  • shows which atoms are bonded to each other
  • shows electrons
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12
Q

Disadvantages of displayed formula

A
  • 2D
  • cannot see electrons
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13
Q

Disadvantages of ball and stick models

A
  • does not show electrons
  • hard to draw when there are many atoms
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14
Q

Disadvantages of dot and cross diagrams

A
  • does not show electrons orbiting
  • hard to draw if there are many atoms
  • 2D
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15
Q

Size of atom

A

1 nanometer (1x10^-10m)

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16
Q

Size of nucleus

A

About 1x10^-14m

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17
Q

Difference between simple and giant covalent structures

A

simple covalent structures have a fixed number of atoms (eg. ammonia) and giant covalent structures have large and variable amounts of atoms

18
Q

Properties of giant covalent structures

A
  • high boiling and melting points (strong intermolecular forces)
  • strong (covalent bonds)
  • cannot conduct electricity (except for graphite and graphene)
  • has a lattice structure
  • not soluble in water
19
Q

Properties of simple covalent molecules

A
  • low boiling and melting points
  • weak intermolecular forces
  • do not conduct electricity as they do not have an overall electric charge
20
Q

What are polymers?

A

large molecules with many small repeating units called monomers that are joined with strong covalent bonds

21
Q

Definition of mixture

A

A mixture consists of two or more elements or compounds that are not chemically combined

22
Q

What is graphene?

A

A single layer of graphite

23
Q

Properties of graphene

A
  • very high melting point
  • very strong
  • conducts electricity well due to having delocalised electrons
  • often used in electronics and composites
24
Q

What are fullerenes?

A
  • Molecules of carbon atoms with hollow shapes
  • based on hexagonal rings of carbon atoms but may also contain rings of five or seven carbon atoms
25
Q

What was the first fullerene that was discovered?

A

Buckminsterfullerene (C60)

26
Q

Properties of fullerenes

A
  • low melting and boiling point (weak intermolecular forces
  • cage like structure (can transport substances inside it eg. medicine)
  • good catalyst (large surface area compared to volume)
  • has a delocalised electron that can carry the charge
  • lightweight
27
Q

Are the intermolecular forces of polymers strong

A

yes, so they remain as solids at room temperature

28
Q

How is ethene converted to polyethene?

A

the double covalent bond between the carbon atoms are broken and is joined to a neighboring molecule

29
Q

Draw the shorthand way of representing a polymer

A

(see goodnotes)

30
Q

Compare diamond to graphite

A

(see goodnotes)

31
Q

Where do we find metals on the periodic table?

A

on the left

32
Q

What is metallic bonding?

A
  • A strong electrostatic force of attraction between positive and delocalised electrons as the delocalised electrons are free to move through (not throughout) the whole structure, leaving positive ions.
33
Q

Advantages of the 2D diagram of metallic bonding

A
  • can see the “sea” of electrons
  • can see every atom easily (none are blocked or covered)
34
Q

Advantages of the 3D diagram of metallic bonding

A
  • shows layer arrangement of the atoms and the giant lattice structure
35
Q

Disadvantages of the 2D diagram of metallic bonding

A
  • cannot see the layer arrangement of the atoms/ the giant lattice structure
  • doesn’t show each indivual electron
36
Q

Disadvantages of the 3D diagram of metallic bonding

A
  • doesn’t show electrons at all
  • can only see outermost atoms
37
Q

Properties of metals

A
  • high melting and boiling point: strong electrostatic forces of attraction so it takes a lot of thermal energy to break the bond
  • malleable: metals consist of layers of ions that are the same size that can slide over each other when the metal is bent, hammered, or pressed
  • electrical conductor: delocalised electrons can carry electrical charge through the metal and move through the structure
38
Q

Why are alloys stronger and harder than pure metals

A
  • the layers are distorted so the particles cannot slide over each other as well
39
Q

Why do alloys not conduct as well as pure metals

A
  • distorted layers cause the delocalised electrons to not be able to pass through the structure as easily.
40
Q

Describe ionic bonding

A

the metal atom loses its outermost electrons and transfers them to the non metal atom to complete the non metal atom’s outer shell. This makes the metal atom a positive ion and the non metal atom a negative ion as there aren’t enough electrons to balance the charge of the protons and vice versa. there is a strong electrostatic force of attraction between the oppositely charged ions

41
Q

Properties of ionic compounds

A
  • high melting and boiling point : the lattice structure and the strong electrostatic forces between the ions require a lot of thermal energy to break
  • Crystalline : this reflects the regular arrangement of teh ions
  • brittle : small distortions in the crystal bring ions with the same charge together and similar charges repel each other, breaking the crystal apart
  • soluble in water : the slightly negative oxygen in the water attracts the positive ions while the slightly negative hydrogen in the water attracts negative ions, pulling the crystal apart
  • do not conduct when solid : the ions cannot move when the ionic compound is solid there cannot carry any charge and cannot conduct electricity
  • conduct when molten/ in solution : the ions are free to move when molten or dissolved and will carry the charge and conduct electricity
42
Q

Draw a ionic bonding diagram for sodium chloride

A

see goodnotes

Chemistry GCSE (9 decks)

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