Atomic Structure and the Periodic Table Flashcards

1
Q

What is an atom?

A

smallest part of an element that can exist

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2
Q

What is an element?

A

a substance made of only one type of atom

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3
Q

Where are elements listed and approximately how many are there?

A
  • listed in periodic table
  • approximately 100
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4
Q

Elements can be classified into 2 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

2 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

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8
Q

What is a mixture?

A

2 or more elements or compounds not chemically combined together

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9
Q

Do mixtures have the same properties as their constituent elements?

A

yes

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10
Q

What are 5 methods through which mixtures can be separated? Do they involve chemical reactions?

A
  1. filtration
  2. crystallisation
  3. simple distillation
  4. fractional distillation
  5. chromatography
    they do not involve chemical reactions
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11
Q

Describe and explain simple distillation

A
  • used to seperate liquid from a solution
  • liquid boils off and condenses in the condenser
  • thermometer will read the boiling point of the pure liquid
  • contrary to evaporation, we get to keep the liquid
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12
Q

Describe and explain crystallisation/evaporation

A
  • evaporation separates a solid dissolved in a solvent from a solvent
  • solution heated until all solvent evaporates, solid stays in vessel
  • crystallisation is similar, but only some of the solvent is removed by evaporation to form a saturated solution
  • the solid starts to crystallise as it becomes less soluble at lower temperatures
  • crystals can be collected and separated from the solvent via filtration
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13
Q

Describe and explain fractional distillation

A
  • separating a mixture of liquids where the liquids have different boiling points
  • apparatus similar to simple distillation, with an additional fractionating column on top of the heated flask - fractionating column contains glass beads to help separate the compounds
  • in industry, mixtures are repeatedly condensed and vapourised
  • column is hot at bottom and cold at top
  • liquids condense at different heights of the column
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14
Q

Describe and explain filtration

A
  • used to separate insoluble solid suspended in a liquid
  • residue gets caught in filter paper (particles too big to fit through holes in paper)
  • 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
  • separate mixture of substances dissolved in a solvent
  • paper chromatography: paper with a spot containing a mixture in a beaker with some solvent, bottom of paper must be in contact with the solvent, solvent level will start to rise, thus separating the spot (mixture) into few spots (components)
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16
Q

What is a separating funnel?

A
  • apparatus for separating immiscible liquids
  • 2 immiscible liquids of different densities will form 2 distinct layers in the separatory funnel
  • we can run off the bottom layer (liquid with greater density) to a separate vessel
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17
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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18
Q

Describe the Bohr/nuclear model & how it came about

A

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

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19
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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20
Q

What did the work of James Chadwick provide evidence for?

A

the existence of neutrons in the nucleus

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21
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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22
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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23
Q

Explain why atoms are electrically neutral

A

they have the same number of electrons and protons

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24
Q

What is the radius of an atom?

A

0.1 nm

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25
Q

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

A

1 x 10^-14m and 1/10000

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26
Q

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

A

atomic number

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27
Q

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

A

protons

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28
Q

Where is the majority of mass of an atom?

A

nucleus

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29
Q

What is the mass number?

A

the total number of protons and neutrons

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30
Q

How does one calculate the number of neutrons using mass number and atomic number?

A

subtract the atomic number from the mass number

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31
Q

What is an isotope?

A

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

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32
Q

Do isotopes of a certain element have the same chemical properties?

A

they have the same chemical properties because they have the same electronic structure

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33
Q

What is the relative atomic mass?

A

the average mass value which takes the mass and abundance of isotopes of an element into account, on a scale where the mass of C(12) is 12

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34
Q

Give the electronic configuration of He (2) to demonstrate how shells are occupied by electrons

A

2

35
Q

Give the electronic configuration of Be (4) to demonstrate how shells are occupied by electrons

A

2,2

36
Q

Give the electronic configuration of F (9) to demonstrate how shells are occupied by electrons

A

2,7

37
Q

Give the electronic configuration of Na (11) to demonstrate how shells are occupied by electrons

A

2,8,1

38
Q

Give the electronic configuration of Ca (20) to demonstrate how shells are occupied by electrons

A

2,8,8,2

39
Q

What are ions?

A

charged particles, formed when atoms lose/gain electrons

40
Q

Compare the boiling/melting point of metals and non-metals

A

metals; high
n-m; low

41
Q

Compare the conductivity of metals and non-metals

A

metals; heat & electricity
n-m; don’y conduct heat/electricity (with the exception of graphite)

42
Q

Compare the appearance of metals and non-metals

A

metals; shiny
n-m; dull

43
Q

Compare the malleability of metals and non-metals

A

metals; yes
n-m; brittle

44
Q

Compare the density of metals and non-metals

A

metals; high
n-m; low

45
Q

Compare the oxides of metals and non-metals

A

metals; basic
n-m; acidic

46
Q

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

A

an ionic compound

47
Q

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

A

a molecular compound containing covalently bonded atoms
atoms share electrons, as opposed to transferring electrons between each other

48
Q

Explain the following terms: solute, solvent, solution, miscible, immiscible, soluble, insoluble

A

solute - substance dissolved in solvent, together they form a solution
miscible refers to the substances (particularly liquids) that mix together
immiscible substances don’t mix (like water and oil)
soluble refers to the substance that can be dissolved in a solvent (like salt in water)
insoluble substance won’t dissolve in a particular solvent

49
Q

What are the columns of the periodic table called?

A

groups

50
Q

What are the rows of the periodic table called?

A

periods

51
Q

Why are elements in the same group similar?

A

they have the same number of outer shell electrons

52
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

53
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 available energy level

54
Q

What are the Group 0 elements more commonly known as?

A

noble gases

55
Q

What makes the periodic table periodic?

A

similar properties of elements occur at regular intervals

56
Q

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

A

they are similar

57
Q

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

A

same number of shells, different number of outer shell electrons

58
Q

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

A

increases

59
Q

Early periodic tables were incomplete and elements were placed in inappropriate groups because they were organised how?

A

strict order of atomic weights

60
Q

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

A

isotopes

61
Q

Mendeleev overcame some problems with the table by doing what?

A

leaving gaps

62
Q

Mendeleev changed the order of some elements based on what?

A

atomic weights

63
Q

Are the majority of elements metals or non-metals?

A

metals

64
Q

Do metals react to form positive or negative ions?

A

positive ions

65
Q

Do non-metals react to form positive or negative ions?

A

negative ions

66
Q

What are elements in Group 1 known as?

A

alkali metals

67
Q

State 3 characteristics of alkali metals

A
  1. one electron in their outer shell
  2. stored under oil (prevent reactions with oxygen or water)
  3. soft (can be cut with a knife)
68
Q

How do Group 1 elements react with n-m? Why are these reactions similar for the different Group 1 elements?

A
  • form ionic compounds which are soluble white solids which form colourless solutions
  • all have 1 electron in their outer shell
69
Q

How to G1 elements react with water?

A

release hydrogen and form hydroxides which dissolve to form alkaline solutions; react vigorously with water fizzing and moving around on the surface of the water

70
Q

How does reactivity change moving down G1? Why?

A
  • reactivity increases
  • atoms get larger & the distance between the nucleus and the outer electrons increases and thus attraction from the nucleus decreases, allowing them to more easily lose electrons
71
Q

State 5 characteristics of Group 7

A
  1. 7 electrons in outer shell
  2. coloured vapours
  3. diatomic molecules (any chemical compound that is made up of only two atoms)
  4. form ionic salts with metals
  5. form molecular compounds with n-m
72
Q

State 4 G7 elements & their states of matter

A
  1. Fluorine (F), pale yellow gas
  2. Chlorine (Cl), pale green gas
  3. Bromine (Br), dark brown liquid
  4. Iodine (I), grey solid
73
Q

State 3 changes that occur in G7 as one moves down the group

A
  1. higher relative molecular mass
  2. higher melting & boiling points
  3. less reactive - less easily gain electrons
74
Q

A more reactive halogen displaces a less reactive one from an aqueous solution of its salt; write the equation and state the colour change seen when chlorine reacts with sodium bromide

A

Cl2 + 2NaBr –> Br2 + 2NaCl
or
Cl2 + 2Br- –> Br2 + 2Cl-

in this reaction, an orange colour of Br2 would appear

75
Q

A more reactive halogen displaces a less reactive one from an aqueous solution of its salt; write the equation and state the colour change seen when chlorine/bromine reacts with sodium iodide

A

Cl2 + 2NaI –> I2 + 2NaCl
or
Cl2 + 2I- –> I2 + 2Cl-

(bromine has same equation, but with Br in place of Cl)
in both reactions, a brown colour of I2 would appear

76
Q

A more reactive halogen displaces a less reactive one from an aqueous solution of its salt; explain the trend in reactivity of halogens in these reactions

A
  • reactivity decreases down the group
  • as we go down the group, atoms get larger, so an incoming electron will be held less tightly by attractive forces from the nucleus
  • that’s why Cl2 displaces Br- and I-
77
Q

Compare G1 metals and transition metals

A
  • both are heat & electricity conductors
  • both are shiny when polished
  • both form ionic compounds with n-m

-transition have higher densities & higher melting points
- transition are less reactive and harder

78
Q

State 3 common characteristics of transition metals

A
  1. ions with different charges
  2. coloured compounds
  3. catalytic properties
79
Q

What is a catalyst?

A

chemical substance that increases the rate of a chemical reaction, is not used up over the course of the reaction

80
Q

State the colour of flame observed when lithium burns in oxygen

A

crimson red

81
Q

State the colour of flame observed when sodium burns in oxygen

A

yellow-orange

82
Q

State the colour of flame observed when potassium burns in oxygen

A

lilac

83
Q

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

A

n-m, gases, low boiling point, unreactive (full outer shell)

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