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Chemistry > Atomic structure and the periodic table and bonding/structure. > Flashcards

Atomic structure and the periodic table and bonding/structure. Flashcards

1
Q

What is an atom?

A

An atom is the smallest part of an element that can exist.

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2
Q

What is an element?

A

An element is a substance that contains only 1 type of atom.

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3
Q

What are compounds?

A

A compound contains atoms of 2 or more elements that are chemically combined.

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4
Q

How can compounds be separated?

A

By chemical reactions or
electrolysis.

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5
Q

Why does the mass of products and mass of reactants equal the same?

A

Because no atoms are lost or made.

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6
Q

What is a mixture?

A

A mixture is 2 or more elements/compounds which are not chemically combined.

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7
Q

What is Filtration used to separate?

A

Soluble solids from insoluble solids.

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8
Q

What is Crystallisation used to separate?

A

To slowly separate a soluble salt from a solution.

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9
Q

What is simple distillation used for?

A

Separating a liquid from a solution.

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10
Q

What is the practical for simple distillation?

A

1) Use a pH probe to analyse the pH of the sample.
2) Set up the equipment.
3) Heat the water to 100 Celsius so that the water goes from liquid to gas.
4) The water collects in the condenser and changes from a gas to a liquid. Collect this pure water in a beaker.
5) When all the water has evaporated measure the mass of the solid that remains to find the amount of solid present.

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11
Q

What is fractional distillation used to separate?

A

To separate out mixtures (usually liquids).

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12
Q

What is chromatography used for?

A

Used to separate the different soluble coloured components of a mixture.

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13
Q

Who discovered the plum pudding model and when did they discover it?

A

Discovered by JJ Thompson in 1897.

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14
Q

What was in the plum pudding model?

A

Negative electrons surrounded by a sea of positive charge.

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15
Q

What happened to the alpha particles in the Marsden and Geiger experiment?

A

Most passed through and some deflected back.

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16
Q

What results did Rutherford conclude?

A

That the positive charge in an atom must be concentrated in a very small area This was named the nucleus.

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17
Q

What model replaced the plum pudding model?

A

The nuclear model.

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18
Q

Who discovered neutrons?

A

James Chadwick.

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19
Q

What is the radius of an atom?

A

0.1 Nanometre.

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20
Q

What are the relative masses of Protons, Neutrons and Electrons?

A

1,1 and very small.

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21
Q

What is the relative charge of a Proton, Neutron and Electron?

A

+1, 0 and -1.

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22
Q

How do you work out the number of neutrons?

A

Mass number - Atomic number.

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23
Q

What is an isotope?

A

Isotopes of an element have the same number of protons but a different number of neutrons.

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24
Q

What type of ions do metals form?

A

They lose electrons to form positive ions.

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25
Q

What type of ions do non-metals form?

A

They gain electrons to form negative ions.

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26
Q

What is electron configuration?

A

The electron configuration of an atom shows how the electrons are arranged around the nucleus in shells.

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27
Q

Who tried to put the first periodic table together in 1864 and how many elements were known?

A

John Newlands tried to put it together. 63 elements were known.

28
Q

How did Newland arrange the known elements?

A

By atomic weight.

29
Q

What did Dimitri Mendeleev do in 1869?

A

He created a table and left gaps for the undiscovered ones. He ordered them in rows and columns.

30
Q

How did Mendeleev arrange the elements?

A

By atomic number (number of protons).

31
Q

What are the elements in Group 0 known as?

A

Noble gases.

32
Q

What do noble gases have and what does this mean?

A

They have a full outer shell of electrons. This means they have a very stable electron configuration making them very unreactive non-metals.

33
Q

What happens to the boiling point of noble gases?

A

Increases as you go down the group.

34
Q

What are group 1 elements known as?

A

They are known as alkali metals.

35
Q

What are group 1 properties?

A

They:
-have one electron in their outermost shell
-have low melting and boiling points that decrease down the group
-become more reactive as you go down the group.

36
Q

Why are alkali metals stored in oil?

A

Because they react very vigorously with oxygen and water, including moisture in the air.

37
Q

When alkali metals react with water what is formed and what is given off?

A

A metal hydroxide is formed and hydrogen gas is given off.

38
Q

What is produced when a metal hydroxide is dissolved in water?

A

An alkaline solution is produced.

39
Q

When alkali metals react with non-metals what is formed?

A

Ionic compounds.
EG sodium + chloride—Sodium Chloride
The alkali metal is sodium
Non-metal is chloride

40
Q

What happens when an ionic compound is formed?

A

When this happens, the metal atom loses one electron to form a metal ion with a positive charge.

41
Q

What are ionic compounds?

A

Giant structures of ions.

42
Q

How are ionic compounds held together?

A

By strong forces of attraction that act in all directions between oppositely charged ions.

43
Q

What are the properties of ionic compounds?

A

-They have high melting and boiling points.
-Do not conduct electricity when solid as ions cannot move.
-Do conduct electricity when in molten or solution as the charged ions are free to move and carry their charge.

44
Q

What is metallic bonding?

A

Bonding between two metals.

45
Q

What is the arrangement in metallic bonding?

A

Regular arrangement of positive ions held together by electrostatic attraction to the delocalised electrons.

46
Q

What is the attraction between in metallic bonding?

A

Between positive ions and delocalised negatively charged electrons.

47
Q

What is an alloy?

A

Mixture that contains a metal and at least one other element.

48
Q

What does an added element do in an alloy?

A

Disturbs the regular arrangement so the layers do not slide over each other.

49
Q

What is steel made from?

A

Iron.

50
Q

What is the arrangement for pure iron?

A

Arranged in layers that can slide over each other easily making it soft and malleable.

51
Q

How does carbon or other elements determine the properties of steel?

A

-Steel with a high carbon is hard and strong.
-Steel with a low carbon content is soft and easily shaped.
-Stainless steel contains chromium and nickel and is hard and resistant to corrosion.

52
Q

What is a covalent bond?

A

A covalent bond is a shared pair of electrons between atoms.

53
Q

What is covalent bonds between?

A

Between two non-metals.

54
Q

What is an example of a covalent bond?

A

For example, a chlorine atom has 7 electrons on its outer shell.
In order to bond with another chlorine atom an electron atom is shared and they both have a complete outer shell.

55
Q

How are covalent bonds shown?

A

Using dot and cross diagrams.

56
Q

What do simple molecules contain ?

A

A relatively small number of non-metal atoms that are joined together by covalent bonds.

57
Q

What are the properties of covalent bonds?

A

No electrical charge so they cannot conduct electricity.
Low melting and boiling points.
This is because they have weak intermolecular forces (forces of attraction between the molecules.)
However large molecules have high melting and boiling points.

58
Q

Diamond

A

Form of carbon.
-Has a giant, rigid covalent structure (lattice).
-Each carbon atom forms four strong covalent bonds with other carbon atoms.
-Strong bonds make it hard to break therefore it has a strong melting point.

59
Q

Graphite

A

Another form of carbon.
- Giant covalent structure and a very high melting point.
-Each carbon atom bonds to three covalent bonds with other carbon atoms.
-Results in a hexagonal structure. Layers held by weak intermolecular forces.
-This means that the layers can slide past each other making it soft and slippery.
-One delocalised electron to conduct heat/electricity.

60
Q

Silicon dioxide

A

-Lattice structure similar to diamond.
-Each oxygen atom is joined to two silicon atoms.
-Each silicon atom is joined to four oxygen atoms.

61
Q

Graphene.

A

-Form of carbon.
-Hexagonal structure, just one atom thick.
-Very strong, a good thermal conductor and electrical conductor and nearly transparent.
-Useful in electronics and composite materials

62
Q

Fullerenes.

A

-Carbon can also form molecules known as fullerenes.
-Hexagonal rings of carbon atoms.
-Molecules have hollow shapes.
-First fullerene discovered was Buckminsterfullerene (C60). Consists of 60 carbon atoms. Most symmetrical and therefore the most stable fullerene.
-Carbon nanotubes are cylindrical fullerenes. Their properties make them very useful for nanotechnology, electronics and materials.
-Fullerenes can be used to deliver drugs to the body; in lubricants; as catalysts; for reinforcing materials.

63
Q

Polymers.

A

-Consist of large molecules.
-Plastics are synthetic polymers.
-Held together by strong covalent bonds. Intermolecular forces are strong.
-Solid at room temperature.
-Poly(ethene) is produced when lots of ethene molecules are joined together.
-It is cheap and strong and is used to make plastic bottles and bags.

64
Q

What are the sizes of coarse, fine and nanoparticles?

A

Coarse particles- Have a diameter between 1* 10-5m and 2.5* 10-6m.
Fine particles- Have a diameter between 100nm and 2500nm or 1* 10-7m and 2.5 * 10-6m.
Nano-Have a diameter between 1nm and 100nm or 1* 10-9m and 1* 10-7m.

65
Q

Nanoparticles.

A

-Only contain a few hundred atoms.
- Can combine to form structures called nanostructures.
-Nanoparticle properties are different from the same materials in bulk. eg Nanoparticles are more sensitive to light, heat and magnetism.
-Used in sunscreens. Provide better skin coverage and more effective from harmful ultraviolet rays.
- Concerns are that they could damage human cells or cause problems to the environment.
Research is leading to the development of new drug delivery systems, catalysts for fuel cells, etc.

Chemistry (10 decks)

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