Bonding Flashcards

1
Q

What is ionic bonding?

A
  • in ionic bonding, atoms lose or gain electrons to form charged particles called ions, which are then strongly attracted to one another (because of the attraction of opposite charges).
  • this strong attraction is known as electrostatic attraction: it gives ionic compounds their high melting and boiling points
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2
Q

What is oxidation?

A
  • when an atom loses electrons
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3
Q

What is reduction?

A
  • when an atom gains electrons
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4
Q

Which groups of elements most readily form ions and why?

A
  • groups 1, 2, 6 and 7

- their shells are nearly full or only have 1 or 2 electrons in the outer shell

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5
Q

What are cations and which groups of elements become them?

A
  • positively charged ions

- groups 1 and 2 as they lose electrons

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6
Q

What are anions and which groups of elements become them?

A
  • negatively charged ions

- groups 6 and 7 as they gain electrons

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7
Q

What happens when the cations collide with the anions?

A
  • they attract each other to form an ionic compound
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8
Q

Why can only elements of opposites sides of the periodic table form ionic compounds?

A
  • because one of them becomes a cation and the other an anion
  • therefore, it’s between a metal and non-metal
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9
Q

What do compounds with ionic bonding always have?

A
  • giant ionic structures
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10
Q

What is the structure of giant ionic structures?

A
  • ions are held together in a closely packed 3D lattice arrangement by the attraction between oppositely charged ions
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11
Q

Describe the electrostatic attraction between the oppositely charged ions

A
  • very strong
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12
Q

What are the properties of ionic compounds?

A
  • high melting and boiling point
  • brittle
  • conduct electricity when molten or in solution, but not as a solid
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13
Q

Why do ionic compounds have high melting and boiling points?

A
  • a lot of energy is needed to overcome the strong electrostatic attraction.
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14
Q

Why are ionic compounds brittle?

A
  • if you hit it, ions of the charge move to become adjacent to each other
  • so they repel
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15
Q

Why do ionic compounds only conduct electricity when molten or in solution?

A
  • in a solid, ions are held in a lattice, so are not free to move
  • in molten or solution, ions are free to move
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16
Q

How do the charges on the ions in the lattice affect the strength of the ionic bonding?

A
  • the higher charge ions are held together by stronger forces of attraction
  • they will also have higher melting and boiling points
17
Q

How do you draw a diagram to represent the positions of ions in sodium chloride?

A
  • draw one now
18
Q

What is a covalent bond?

A
  • atoms share a pair of electrons with other atoms to make full outer shell
19
Q

What is the strength of attraction between the shared electrons and the nuclei in covalent bonding?

A
  • a strong attraction
20
Q

What are simple molecular/covalent substances?

A
  • the atoms within a molecule are held together by very strong covalent bond
  • talk about molecules!!
  • however, the forces of attraction between the molecules (intermolecular forces) are very weak
21
Q

What is the result of weak intermolecular forces?

A
  • very low melting and boiling points

- the molecules are easily parted from each other

22
Q

What are the properties of simple covalent substances?

A
  • low melting/boiling point

- do not conduct electricity: there are no delocalised electrons or ions

23
Q

What are giant covalent structures?

A
  • a lattice of atoms that are joined by covalent bonds
  • talk about atoms!! not ions or molecules
  • all atoms are bonded to each other by strong covalent bonds
24
Q

What are the properties of giant covalent structures?

A
  • really high melting and boiling points: it takes a lot of energy to break them
  • do not conduct electricity: except graphite
  • usually insoluble in water
25
Q

Give 3 examples of giant covalent structures

A
  • diamond
  • graphite
  • silicon dioxide
26
Q

Draw and describe diamonds

A
  • each carbon atom forms forms four covalent bonds in a very rigid giant covalent structure
  • very high melting point
  • does not conduct electricity
  • very hard because atoms cannot be broken. you would have to break very strong covalent bonds. used for cutting tools
27
Q

Draw and describe graphite

A
  • each carbon atom forms three covalent bonds, creating layers which are free to slide over each other
  • strong covalent bonds within each layer
  • conducts electricity: delocalised electrons between layers
  • soft and flaky: layers of C atoms can slide over each other
  • very high melting point
  • used as lubricant, soft and slippery
28
Q

What are giant metallic structures?

A
  • a giant structure of positive ions surrounded by a sea of delocalised electrons
  • the attraction between the positive ions and the electrons is called metallic bonding
29
Q

Draw a metallic lattice

A
  • have a lattice of cations, at least 3 x 3

- sea of delocalised electrons

30
Q

What are the properties of giant metallic structures?

A
  • conductors of electricity and heat as solid and liquid: delocalised electrons are free to move
  • malleable: layers of cations can slide over each other,
  • high melting point( not as high as ionic): strong electrostatic attraction between cations and delocalised electrons, so lots of energy to overcome it