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GCSE CHEM > Topic 1: Atomic Structure and the Periodic Table > Flashcards

Topic 1: Atomic Structure and the Periodic Table 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 of only one type of atom

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3
Q

How are the elements listed and approximately how many are there ?

A

They are listed in the periodic table ; there are approximately 100

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4
Q

Elements can be classified into two groups based on their properties ; what are these groups ?

A

Metals and non-metals

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5
Q

Elements may combine through chemical reactions to form new products ; what are these new substances called ?

A

Compounds

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6
Q

What is a compound ?

A

Two or more elements combined chemically in fixed proportions which can be represented by formulae

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7
Q

Do compounds have the same properties as their constituent elements ?

A

No , they have different properties

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8
Q

What is a mixture ? Does it have the same chemical properties as its constituent materials ?

A

A mixture consists of two or more elements or compounds not chemically combined together ; it does have the same chemical properties

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9
Q

What are the methods through which mixtures can be seperated (five) ? Do these involve chemical reactions ?

A

Filtration, crystallisation, simple distillation, fractional distillation and chromatography; they do not involve chemical reactions

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10
Q

Describe and explain simple distillation

A

Simple distillation is used to separate liquid from a solution - the liquid boils off and condenses in the condenser . The thermometer will read the boiling point of the pure liquid . Contrary to evaporation , we get to keep the liquid

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11
Q

Describe and explain evaporation

A

Evaporation is a technique for separation of a solid dissolved in a solvent from a solvent

The solution is heated until all the solvent evaporates; the solids stays in the vessel.

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12
Q

What is crystallisation ?

A

Crystallisation is similar to evaporation , but we only remove some of the solvent by evaporation to form a saturated solution (the one where no more solid can be dissolved). Then, we cool down the solution. As we do it, the solid starts to crystallise, as it becomes less soluble at lower temperatures. The crystals can be collected and separated from the solvent via filtration.

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13
Q

Describe and explain fractional distillation

A

Fractional distillation is a technique for separation of a mixture of liquids.
It works when liquids have different boiling points.
The apparatus is similar to the one of simple distillation apparatus, with the additional fractionating column placed on top of the heated flask.
The fractionating column contains glass beads. It helps to separate the compounds.
In industry, mixtures are repeatedly condensed and vapourised. The column is hot at the bottom and cold at the top. The liquids will condense at different heights of the column

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14
Q

Describe and explain filtration

A

Filtration is used to separate an insoluble solid suspended in a liquid.
The insoluble solid (called a residue) gets caught in the filter paper, because the particles are too big to fit through the holes in the paper.
The filtrate is the substance that comes through the filter paper.
Apparatus: filter paper + funnel.

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15
Q

Describe and explain chromatography

A

Chromatography is used to separate a mixture of substances dissolved in a solvent.
In paper chromatography, we place a piece of paper with a spot containing a mixture in a beaker with some solvent. The bottom of the paper has to be in contact with the solvent. The solvent level will slowly start to rise, thus separating the spot (mixture) into few spots (components).

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16
Q

Describe the plum-pudding model

A

The atom is a ball of positive charge with negative electron embedded in it.

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17
Q

Describe the Bohr/ nuclear model and how it came about

A

The nuclear model suggests that electrons orbit the nucleus at specific distance (shells ) - it came about from the alpha scattering experiments

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18
Q

Later experiments led to the discovery of smaller , positive particles in the nucleus; what are these particles called ?

A

Protons

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19
Q

What did the work for James Chadwick provide evidence for ?

A

The existence of neutrons in the nucleus

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20
Q

Describe the structure of an atom

A

The atom has a small central nucleus ( made up of protons and neutrons) around which there are electrons

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21
Q

State the relative masses and relative charges of the proton , neutron and electron

A

Masses: 1, 1, very small; Charges: 1, 0, -1

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22
Q

Explain why atoms are electrically neutral

A

They have the same number of electrons and protons

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23
Q

What is the radius of an atom

A

0.1 nm

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24
Q

What is the radius of a nucleus and what is it compared to that of the atom ?

A

1 x 10^-14 m and 1/10000

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25
Q

What name is given to the number of protons in the nucleus ?

A

Atomic number

26
Q

Atoms of the same element have the same number of which particle in the nucleus

A

Protons

27
Q

Where is the majority of mass of an atom ?

A

The nucleus

28
Q

What is the mass number ?

A

The total number of protons and neutrons

29
Q

How do you calculate the number of neutrons using mass number and atomic number ?

A

Subtract the atomic number from the mass number

30
Q

What is an isotope ? Do isotopes of a certain element have the same chemical properties ?

A

Atoms of the same element (same proton number) that have a different number of neutrons.

They have the same chemical properties as they have the same electronic structure

31
Q

What are ions ?

A

Atom with an pverall charge . They are formed when atoms lose electrons (positive ions) or gain (negative ions) electrons

32
Q

What is formed when a metal reacts with a reacts with a non-metal ?

A

An ionic compound ( made of positive and negative ions)

33
Q

What is formed when a non-metal reacts with a non-metal ?

A

A molecular compound containing covalently bonded atoms

Atoms share electrons , as opposed to transferring electrons between each other

34
Q

The colummns of the periodic table are called … ?

A

Groups

35
Q

The rows of the periodic table are called … ?

A

Periods

36
Q

Are elements in the same group similar or different ?

A

They have similar chemical properties , as they have the same number of outer shell electrons .

37
Q

In terms of energy levels , what are the differences between elements of the same period ?

A

They have the same number of energy levels

38
Q

Electrons occupy particular energy levels , with each electron in an atom at a particular energy level ; which available energy level do electrons occupy ?

A

The lowest availably energy level

39
Q

The elements of Group 0 are more commonly known as … ?

A

The noble gases

40
Q

What makes the periodic table periodic ?

A

Similar properties of elements occur at regular intervals

41
Q

Elements in the same geoup have the same number of electrons in their outer shell ; what does this tell us about their chemical properties ?

A

They have similar chemical properties

42
Q

In terms of shells , what is the difference between elements in the same period ?

A

They have the same number of shells

43
Q

What change in shell number is seen as one moves down a group ?

A

The number of shells increases

44
Q

Early periodic tables were incomplete and elements were placed in inappropriate groups if what was to be followed ?

A

The strict order of atomic weights

45
Q

Knowledge of what made it possible to explain why the order based on atomic weights was not always correct ?

A

Isotopes

46
Q

Mendeleev overcame some problems with the table by doing what ? He also changed the order of some elements based on what ?

A

Leaving gaps ; atomic weight

47
Q

The majority of elements are … ?

A

Metals

48
Q

Elements that react to form positive ions are … ?

A

Metals

49
Q

Elements that do not form positive ions are … ?

A

Non-metals

50
Q

Elements that do not form positive ions are … ?

A

Non- metals

51
Q

Elements in Group 1 are known as … ?

A

The alkali metals

52
Q

State three characterisitics of the Alkali Metals

A

All have one electron in their outer shell; have low density; are stored under oil (to prevent reactions with oxygen or water); are soft (can be cut with knife).

53
Q

How do group 1 elements react with non-metals ? Why are these reactions similar for the different Group 1 elements ?

A

They form ionic compounds which are soluble white solids which form colourless solutions - they all have one electron in their outer shell

54
Q

How do group 1 elements react with water ?

A

They release hydrogen ; react vigorously with water fizzing and moving around on the surface of the water

55
Q

How does reactivity change moving down group 1 ? Why ?

A

Reactivity increases as the atoms get larger and the distance between the nucleus and the outer electrons increases and thus attraction from the nucleus decreases , allowing them to more easily lose electrons

56
Q

State five characteristics of group 7

A
  • 7 electrons in outer shell
  • Coloured vapours
  • diatomic molecules
  • form ionic salts with metals
  • form molecular compounds with non-metals
57
Q

State three changes thay occur in group 7 as one moves down the group

A
  • higher relative molecular mass
  • higher melting and boiling point
  • less reactive - less easily gain electrons
58
Q

What is a catalyst ?

A

A catalyst is a chemical substance that increases the rate of a chemical reaction.

It is not used up over the course of the reaction.

59
Q

Describe the properties of noble gases . Discuss the trend in bioling point down the group

A

Non-metals, gases, low boiling points, unreactive (full outer shell; they don’t easily accept or lose electrons).

The boiling point increases down the group, as the atoms get heavier.

60
Q

What is the relative atomic mass ?

A

The average mass value which fake the mass and abundance of isotopes of an element into account

GCSE CHEM (7 decks)

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