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Chemistry 1 > Metallic bonding > Flashcards

Metallic bonding Flashcards

1
Q

What are the properties of metals?

A

Conduct electricity, conduct heat, lustrous, high melting points, dense, malleable, hard, high tensile strength, reductants.

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2
Q

How do metals conducts heat?

A

The heat causes the delocalised electrons to gain energy which makes them move faster and collide more frequently, allowing them to transfer the heat to other electrons.

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3
Q

Why are metals lustrous?

A

Metals contain delocalised electrons which reflect the light from metals this gives the metals a shiny appearance.

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4
Q

Why are metals dense?

A

Metals have high densities because the particles in the metallic lattice are tightly packed together.

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5
Q

Why do metals have high melting points and are hard?

A

Metals are held together by strong metallic bonds from the electrostatic attraction between the cations and the delocalised electrons.

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6
Q

Why are metals good conductors of electricity?

A

Metals contain negatively charged electrons that are free to move. Therefore they can carry a charge through a metal.
When an electric field is applied the electrons will move to the positive and therefore create an electric current.

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7
Q

Why are metals malleable and ductile?

A

Metals are bonded together by electrostatic forces which are non directional, this means atoms may slide over each other with out disrupting the attraction.

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8
Q

What are the limitations to the metallic bonding model?

A

The model does not allow for any exceptions and does not explain them. Eg. mercury liquid at room temp, differences in melting temps and magnetic properties.

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9
Q

What is an alloy?

A

An alloy is a metal that has been combined with another metal or sometimes non metal, resulting in a change of properties that will better suit the metals use.

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10
Q

What are the different types of alloys?

A

Substitutional: one atom is subbed for a another atom of the same size. Layers of lattice cannot easily move, alloy is less malleable and harder than pure metal.
Interstitial: Smaller atoms fit between gaps in the pure metals lattice. layers of the lattice can’t move easily so alloy is less malleable.

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11
Q

What are some benefits of alloying?

A

Usually depends on the type of alloy created.

  • improved strength
  • resistance to corrosion
  • less malleable
  • reduced melting temp
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12
Q

Alloying: True of False

  1. Pure metals will be more malleable than alloy
  2. The alloy will be more resistant to corrosion than pure metal
  3. Pure metal will have higher electrical conductivity than alloy
  4. Alloy will usually have higher meting temp than the two pure metals
A
  1. True: alloys are less malleab
  2. True: alloys have improved benefits
  3. True: alloys have improved benefits
  4. False: alloys have lower melting points because their bond are weakened by the interruption of another element
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13
Q

Alloying: True or False

  1. Crystals of one metal will be distributed throughout the crystals of the other metal
  2. Small atoms may fit into the lattice spaces between cations of the metallic lattice
  3. Metal ions of one kind may replace other metal ions in the lattice
  4. An alloy produces a compound with a distinct formula
A
  1. True
  2. True: interstitial
  3. True: substitutional
  4. False: There is no certain amount of metals that need to be added to each other to create an alloy. You can use as much or as little as you want to create an alloy
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14
Q

The bonding in metals is beast explained as attraction between…?

A

Positive ions and in a sea of electrons.

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15
Q

What are some properties of s block metals?

A

Form compounds that are usually white.

  • Alkali metals are very reactive, low density, lowish melting point, large atomic radius
  • Alkaline Earth metals are reactive (less than alkali), harder, higher melting points
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16
Q

What are some properties of d block metals?

A

Transition metals form colourful compounds (expect find and sc). Fe, Co, Ni are magnetic, form ions with different charges.

17
Q

How does the ball bearing model explain a metals malleability?

A

If a metal has a perfect arrangement of atoms with fewer Crystals and crystal grains the metal will be very malleable because the atoms can easily slide over one another.

  • metals with large grains have fewer dislocations and bend easily
  • metals with small grains have many dislocations and do not bend easily.
18
Q

What is work hardening?

A

Bending or hammering metals causes their crystal grains to become smaller, meaning the metal is harder to bend, causing the metal to become toughened. Bending metal in the same area causes the particles on either side of the bend to become more closely packed.

19
Q

What is annealing?

A

Annealing is when metals are heated to high temperatures and the cooled slowly. This creates larger crystals.

20
Q

Are metals brittle?

A

Metals are not usually brittle. They are ductile and malleable.

21
Q

Copper is a widely used metal. What is the main reason for its widespread use?

A

It’s ability to conduct heat and electricity very well. Most house hold wiring is made using copper. It’s also used in cooking utensils for its food thermal conductivity.

22
Q

Why are transition metals used for building instead of main group metals?

A

Transition metals are stronger because of their smaller atoms that are packed more closely, allowing stronger bonding and they are less reactive.

23
Q

Why are work hardened metals, alloys and quenched metals more brittle?

A

These processes all produces smaller crystal grains. These smaller crystal grains prevent the layers of atoms form sliding over each other. Alloying increases the hardness by introducing atoms that prevent the layers from sliding over each other.

24
Q

Why does annealing produce better electrical conductivity than quenching?

A

Annealing allows metals to cool slowly which creates larger crystals because particles have more time to arrange in a perfect arrangement. These larger crystals allow for an easier flow of delocalised electrons. The more crystal boundaries there are creates a disruption in electron flow.

25
Q

Why are metals cold on cold days?

A

Metals are good thermal conductors because the delocalised electrons can bump into other metal ions, transferring heat energy. The metal feels cold because it quickly conducts some of your body heat away from you.

26
Q

What are the ways to change a metals properties? and what are they? (5)

A
  • Annealing: heated high then cooled slow
  • Quenching: heated and cooled fast
  • Tempering: quenched metals heated mod and cooled slow
  • Work hardening: repeated bending of metal
  • Alloying: mixing two of more metals
27
Q

What are the ways to change a metals properties and what are the new properties?

A
  • Annealing: softer and more malleable
  • Quenching: hard and more brittle
  • Tempering: softer and stronger
  • Work hardening: harder more brittle
28
Q

What is copper electron configuration?

A

1s2 2s2 2p6 3s2 3p6 4s1 3d10

It loses an electron from 4s to make the 3d subshell more stable.

29
Q

What is the electron configuration of Chromium?

A

1s2 2s2 2p6 3s2 3p6 4s1 3d5

It loses an electron from 4s to make the 3d subshell more stable.

30
Q

Why does magnesium have a higher melting point than sodium?

A

Magnesium has a higher melting point because it has a higher core charge so the electrostatic attraction takes more energy to break.

31
Q

What are the properties of transition metals compared with main group metals?

A
  • harder, denser, higher mp
  • form ions with different charges
  • form coloured compounds
  • some are magnetic
  • are not very reactive (weak reductants)
32
Q

How to identify them most reactive metals?

A
  • react vigorously with water to form a salt and hydrogen
  • react with oxygen in air so must be stored in oil
  • less reactive metals will react an acid to form a salt and hydrogen
  • metals that do not react with acids are called noble metals or native metals
33
Q

What is electrolysis?

A

Is the process by which ionic substances are decomposed (broken down) into simpler substances when an electric current is passed through them.

34
Q

How are very reactive metals separated from their ores?

A

Electrolysis: K, Na, Ca, Mg, Al.

35
Q

How are moderately reactive metals separated from their ores?

A

Blast furnace which heats metals to a very high temperature with carbon. Zn, Fe, Sn, Pb

36
Q

What metals only need to be heated to be extracted from their ores?

A

Cu, Hg, Ag

37
Q

What are the properties of metals that have larger crystals?

A

Better conductivity and malleability.

38
Q

What does the metallic bonding model explain?

A

The metallic bonding model explains electrical conductivity, malleability, high melting and boiling points,
high density and hardness, but it does not explain variations in these properties.

Chemistry 1 (8 decks)

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