Atoms, Bonds and Groups - the Periodic Table Flashcards Preview

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Flashcards in Atoms, Bonds and Groups - the Periodic Table Deck (76):
1

What is sometimes referred to as the fourth state of matter?

Plasma is sometimes referred to as the fourth state of matter.

2

Who was the first to compile an extensive list of elements?

Antoine-Laurent Lavoisier, assisted by his wife, was the first to compile an extensive list of elements.

3

Who was the first to use letter-based symbols for elements?

Jöns Jakob Berzelius (1828) published a table of atomic weights and determined the composition by mass of many compounds, he was also the first to use letter-based symbols for elements.

4

Who proposed the law of triads?

Johann Wolfgang Döbereiner (1829) proposed the law of triads.

5

What is the law of triads?

"nature contains triads of elements where the middle element has properties that are an average of the other two members of the triad when ordered by atomic weight."

6

Who devised an early form of the periodic table by arranging elements in a spiral on a cylinder by increasing atomic weight?

Alexandre-Emile Béguyer de Chancourtois (1862) devised an early form of the periodic table arranging elements in a spiral on a cylinder by increasing atomic weight, elements with similar properties were aligned vertically.

7

Who was the first to devise a proper periodic table as we currently know it with the elements arranged in order of their relative atomic weights?

John Newlands was the first to devise a proper periodic table as we currently know it with elements arranged in order of their relative atomic weights.

8

Who developed the 'law of octaves'?

John Newlands built on the work of Döbereiner and his 'triads' and developed a 'law of octaves'.

9

After Newlands, who published a more advanced version of the periodic table based on atomic masses which is the basis of the table used today?

Dmitri Mendeleev, four years after Newlands, published a more advanced form of the periodic table also based on atomic masses which is the basis of the table used today.

10

What was super clever about Dmitri Mendeleev's periodic table?

Gaps were left in the table if there wasn't a known element which fit. Due to the repeating pattern of elements, the properties of elements in these gaps could be predicted.

11

What was a disadvantage of Mendeleev's table?

A disadvantage of Mendeleev's table was that isotopes had yet to be discovered and there was no place for them in the table.

12

Who, in 1869 compiled a periodic table containing 56 elements arranged in order of atomic weight, based on periodicity of properties such as molar volume?

Julis Lothar Meyer (1869), a German chemist, compiled a periodic table containing 56 elements arranged in order of atomic weight, based on periodicity of properties such as molar volume.

13

Who determined the atomic number for each of the elements?

Henry Moseley (1913) determined the atomic number for each of the elements.

14

What is the atomic number?

Atomic number is the number of positive charges in the atomic nucleus.

15

What is a period? (in the periodic table)

A period is a horizontal row of elements in the periodic table.

16

Give examples of 'semi-metals' or 'metalloids'.

Elements such as silicon and germanium are called semi-metals or metalloids.

17

What is unique about the semi-metals or metalloids?

The semi-metals or metalloids display properties between those of a metal and a non-metal.

18

Chemical reactions involve which electrons?

Chemical reactions involve electrons in the outer shell.

19

Elements within a ....... have atoms with the same number of electrons in their outer shells.

Elements in a group have atoms with the same number of electrons in their outer shells.

20

What property of elements in the same group explains why they have similar chemical behaviour?

Elements within a group have atoms with the same number of electrons in their outer shells, this is why they have similar chemical behaviour.

21

What are the factors that affect ionisation energies?

The factors which affect ionisation energies are:

  • nuclear charge
  • distance from the nucleus
  • electron shielding

22

TRUE or FALSE

Ionisation energies show a general decrease across a period?

FALSE!

Ionisation energies show a general increase across a period.

23

What are the factors which contribute to the increase in ionisation energy across a period?

  • Across each period the number of protons increases so there is more attraction acting on the electrons
  • As electrons are added to the same shell, the outer shell is drawn inwards slightly. - There is still the same number of inner shells, so electron shielding will hardly change
  • Across a period the attraction between the nucleus and the outer electrons increases, so more energy is needed to remove an electron

24

TRUE or FALSE

There is an increase in atomic radius across a period?

FALSE!

There is a decrease in atomic radius across a period because the increased nuclear charge pulls the electrons inwards.

25

TRUE or FALSE

Down a group, first ionisation energies decrease?

TRUE!

Down a group first ionisation energies decrease.

26

Why does the first ionisation energy decrease down a group?

The first ionisation energy decreases down a group because the attraction between the nucleus and the outer shell electrons decreases down a group so less energy in needed to remove an electron.

27

What is the trend in boiling points across the periodic table?

Groups 1 → 4 - general increase in boiling points

Groups 4 → 5 - sharp decrease in boiling points

Groups 5 → 0 comparatively low boiling points

28

Why does group 4 have relatively high boiling points whilst group 5 shows much lower boiling points?

There is a distinct change between groups 4 & 5 in both physical structure and the forces holding the structure together - from giant to simple, from strong to weak forces.

29

Why are group 2 called the alkaline earth metals?

The elements in group 2 all have hydroxides which are alkaline which is why they are called the alkaline earth metals.

30

What are the properties of the group 2 elements?

The properties of the group 2 elements:

  • reasonably high melting and boiling points
  • light metals with low densities
  • form colourless compounds

31

Where is the highest energy electron in group 2 elements?

Group 2 elements have their highest energy electrons in an s sub-shell.

32

Which groups of the periodic table form the 's block'?

Group 1 + group 2 form the s block of the periodic table.

33

How many electrons are in the outer shell of a group 2 element?

Each group 2 element has 2 electrons in its outer shell.

34

TRUE or FALSE

All group 2 metals are not very reactive metals?

FALSE!

Group 2 elements are reactive metals.

35

TRUE or FALSE

Group 2 elements are strong reducing agents?

TRUE!

Group 2 elements are strong reducing agents.

36

Reactivity increases as you go ............ group 2, reflecting the ease of electrons lost.

Reactivity increases as you go down group 2, reflecting the ease of electrons lost.

37

Group 2 metals react with oxygen to produce what?

Group 2 metals react vigorously with oxygen in a redox reaction that produces a metal oxide.

38

Group 2 metals react with water to form what?

Group 2 metals react with water to form a metal hydroxide and hydrogen gas.

39

TRUE or FALSE

The reaction rate of group 2 metals with water decreases as you go down the group?

FALSE!

The reaction rate of group 2 metals with water increases as you move down the group.

40

TRUE or FALSE

Group 2 oxides and hydroxides are bases?

TRUE!

Group 2 hydroxides and oxides are bases.

41

Group 2 oxide/hydroxide + acid  →  ?

Group 2 oxide/hydroxide + acid  →  salt + water

42

Group 2 oxide + water → ?

Group 2 oxide + water → metal hydroxide(aq) 

43

Define thermal decomposition

Thermal decomposition is the breaking up of a chemical substance with heat into at least two chemical substances.

44

What are the group 2 metal carbonates thermally decomposed into?

The group 2 metal carbonates are decomposed by heat forming the metal oxide and carbon dioxide gas.

45

TRUE or FALSE

The group 2 metal carbonates become more difficult to decompose with heat as you move down the group?

TRUE!

The carbonates of group 2 elements become more difficult to decompose with heat as you move down the group.

46

What is calcium hydroxide used for?

Calcium hydroxide is used as lime by farmers and gardeners to neutralise acid soils.

47

What is magnesium hydroxide used for?

Magnesium hydroxide is known as 'milk of magnesia' and is used to relieve indigestion. It works by neutralising excess acid in the stomach.

48

What are the group 7 elements collectively known as?

The group 7 elements are known as the halogens.

49

TRUE or FALSE

Halogens generally have high melting and boiling points?

FALSE!

Halogens generally have low melting and boiling points.

50

Halogens generally exist in paired molecules, what is their scientific name?

Halogens exist as diatomic molecules, X2.

51

TRUE or FALSE

The boiling point of halogens increases down the group.

TRUE!

The boiling point of halogens increases down the group.

52

How many electrons are in the outer shells of the group 7 elements?

The group 7 elements have 7 electrons in their outer shells.

53

In which orbital are the highest energy electrons of halogens found?

The highest energy electrons of the halogens are found in a p orbital.

54

How many electrons are found in the p orbital of the group 7 electrons?

Each group 7 element has an outer p orbital containing 5 electrons.

55

What are the most reactive non-metals in the periodic table?

The halogens are the most reactive non-metals in the periodic table.

56

TRUE or FALSE

Halogens are strong reducing agents?

FALSE!

Halogens are strong oxidising agents.

57

When halogens gain electrons, to which sub-shell are they added?

When halogens gain electrons they are added to a p sub-shell to form a halide ion with a -1 charge.

58

TRUE or FALSE

The reactivity of halogens increases down the group?

FALSE!

The reactivity of halogens decreases down the group.

59

Why does the reactivity of halogens decrease down the group?

The reactivity of halogens decreases down the group:

  • atomic radius increases
  • electron shielding increases

60

Define a displacement reaction?

A displacement reaction is a reaction in which a more reactive element displaces a less reactive element from an aqueous solution of the latter's ions.

61

Define disproportionation.

Disproportionation is the oxidation and reduction of the same element in a redox reaction.

62

Chlorine reacts with water to form what?

Chlorine reacts with water to form a mixture of hydrochloric acid and chloric acid.

63

Why is chlorine added to water?

Small amounts of chlorine are added to drinking water to kill bacteria and make the water safer to drink.

64

What symbol is often used to represent any halogen?

The symbol 'X' is often used to represent any halogen.

65

TRUE or FALSE

Group 7 elements have a giant lattice structure?

FALSE!

Group 7 elements have a simple molecular structure.

66

How is fluorine found as an element?

Fluorine is found as a pale yellow-green gas.

67

TRUE or FALSE

Halide compounds are very unstable.

FALSE!

Halide compounds are mainly very stable.

68

What is the main use of sodium chloride?

Sodium chloride is used as table salt.

69

What is sodium fluoride used for?

Sodium fluoride is added to toothpaste to prevent tooth decay.

70

What is the main use of calcium fluoride?

Calcium fluoride is used to make lenses focus infrared light.

71

Why are some environmentalists concerned about the addition of chlorine to drinking water?

Some environmentalists are concerned about the addition of chlorine to water as chlorine reacts with organic matter to form traces of chlorinated hydrocarbons, suspected of causing cancer.

72

What is the test for halides?

  1. An unknown halide is dissolved in water
  2. AgNO3(aq) is added
  3. A silver halide precipitate forms
  4. The silver halide precipitate is coloured, which indicates which halide has formed
  5. If unsure, add NH3(aq). Different halides have different solubilities in ammonia
    • chloride is soluble in dilute NH3(aq)
    • bromide is soluble in concentrated NH3(aq)
    • iodide is insoluble in concentrated NH3(aq)

73

On addition of AgNO3, what colour is a chloride precipitate?

A chloride precipitate is white.

74

On addition of AgNO3, what colour is an iodide precipitate?

An iodide precipitate is yellow.

75

On addition of AgNO3, what colour is a bromide precipitate?

A bromide precipitate is cream.

76