The Periodic Table (1.2) (M) Flashcards

1
Q

What are the elements in the periodic table are arranged in order of? Why?

A

atomic (proton) number so that elements with similar properties are in columns, known as groups

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2
Q

What is in common between elements in the same group? What does this mean?

A

they have the same number of electrons in their outer shell (outer electrons) and this gives them similar chemical properties

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3
Q

In the periodic table, as you move down group 7, the boiling point increases. Why is this?

A
  • the formula mass of atoms increase
  • the intermolecular forces between the atoms become stronger
  • more energy is needed to overcome these intermolecular forces

same for all non-elements (bar G8) as they often form diatomic molecules

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4
Q

Before the discovery of protons/neutrons/electrons, how did scientists attempt to classify elements?

A

by arranging them in order of their atomic weights

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5
Q

What is the problem with early periodic tables?

A

They were incomplete and some elements were placed in inappropriate groups (not matching properties) if the strict order of atomic weights was followed

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6
Q

How did Mendeleev overcome the problems with the early periodic table?

A

He left gaps for elements that he thought had not been discovered and in some places changed the order based on atomic weights

he only did 7 groups, leaving out the noble gases as they had not been discovered by 1869

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7
Q

2 points

Why was Mendeleev’s table considered accurate?

A
  1. Elements with properties predicted by Mendeleev were later discovered and filled the gaps.
  2. Knowledge of isotopes made it possible to explain why the order based on atomic weights was not always correct.
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8
Q

What ion do metals form?

A

positive

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9
Q

What are the elements tat do not form positive ions?

A

non-metals

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10
Q

The majority of elements are.. (metals or non-metals)

A

metals

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11
Q

Where are metals and non-metals found on the periodic table?

A

Metals are found to the left and towards the bottom of the periodic table.

Non-metals are found towards the right and top of the periodic table.

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12
Q

3 factors

The electrostatic forces of attraction depend on which factors

A
  • distance between outermost electrons and nucleus
  • the number of occupied inner shells (energy levels) which provide a shielding effect
  • the size of the positive charge on the nucleus (called the nuclear charge)
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13
Q

What the elements in Group 0 of the periodic table are called?

A

the noble gases

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14
Q

What are the chemical properties of the noble gases? Why?

A

They are unreactive and do not easily form molecules because their atoms have stable arrangements of electrons (full outer shell)

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15
Q

2 needed

What are the physical properties of noble gases?

A
  • low boiling point
  • low density
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16
Q

How many electrons do noble gases have in their outer shell? What is the exception?

A

The noble gases have eight electrons in their outer shell, except for helium, which has only two electrons.

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17
Q

How does the boiling point of noble gases correspond with their position in the group?

A

The boiling points of the noble gases increase with increasing relative atomic mass (going down the group)

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18
Q

Where are the noble gases placed in the periodic table?

A

to the right of Group 7

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19
Q

What are the elements in Group 1 of the periodic table are known as?

A

The alkali metals

20
Q

Why do the alkali metals have characteristic properties? (number of electrons in outer shell)

A

because they have a single electron in their outer shell

21
Q

3 needed

What are the physical properties of alkaline metals?

A
  • are soft (they can be cut with a knife)
  • have relatively low melting points
  • have low densities
22
Q

Why do the alkali metals have to be stored in oil?

A

To prevent them from reacting with oxygen in the air

23
Q

What is formed when the alkaline metals react with water?

A

Metal hydroxide and hydrogen gas

24
Q

What happens to the pH of water when an alkaline metal reacts with it?

A

rises above pH 7

If universal indicator is present, it will look blue or purple

25
Q

Describe what you would observe when lithium, sodium and potassium react with water

A

Lithium: fizzes steadily; slowly becomes smaller until it disappears

Sodium: fizzes rapidly; melts to form a ball; quickly becomes smaller until it disappears

Potassium: burns violently with sparks and a lilac flame; quickly melts to form a ball; disappears rapidly, often with a small explosion

26
Q

Describe the reaction of an alkaline metal and an oxygen

A

Metal oxide formed.

The alkali metals burn vigorously when heated and placed in a gas jar of oxygen. The oxide forms as white smoke

27
Q

4 marks

Describe the reaction between an alkaline metal and chlorine gas

A

The group 1 elements react vigorously with chlorine. The products of the reactions are chlorides. At room temperature the chlorides are white solids. They dissolve in water to form colourless solutions.

28
Q

2 needed

What are the physical properties of an ionic compound of an alkaline metal?

A
  • white solid
  • dissolve in water, giving a colourless solution
29
Q

In Group 1, how does the boiling point of the elements correspond with their position in the group?

A

In Group 1, the boiling point of the elements decreases going down the group

30
Q

Why do group 1 elements get more reactive going down the group?

A
  • They have a larger atom going down the group
  • Group 1 elements must lose an electron to obtain a full outer energy level
  • Larger atoms lose electrons more easily
  • Due to weaker electrostatic force of attraction (between electron lost and nucleus) because of:
    • shielding effect from increased number of energy levels
    • greater distance between nucleus and electron
    • nuclear charge outweighed by these factors
31
Q

why should hydrogen not be placed in Group 1/

A

It is a non-metal

32
Q

What are the elements in Group 7 of the periodic table are known as?

A

The halogens

33
Q

Why do the group 7 elements have similar reactions?

A

because they all have 7 electrons in their outer shell

34
Q

3 things

In Group 7, the further down the group an element is, the higher its

A

relative molecular mass, melting point and boiling point

35
Q

Are the halogens metals or non-metals?

A

non-metals

36
Q

What do the molecules of halogens consist of?

A

a pair of atoms (diatomic molecules)

37
Q

Describe the reaction between chlorine, bromine and iodine with a metal?

A

Chlorine: metal burns vigorously to produce orange-brown iron(III) chloride

Bromine: metal burns quickly to produce red-brown iron(III) bromide

Iodine: metal reacts slowly in iodine vapour to produce grey iron(II) iodide

38
Q

Describe the reaction between chlorine, bromine and iodine with a non-metal?

A

Chlorine: explodes with a flame or in sunlight, forming hydrogen chloride

Bromine: vigorous reaction when warmed with hydrogen, forming hydrogen bromide

Iodine: very slow reaction when heated strongly, forming some hydrogen iodide

39
Q

In Group 7, how does the reactivity of the elements correspond with their position in the group?

A

In Group 7, the reactivity of the elements decreases going down the group.

40
Q

What are the physical properties of group 7 elements?

A
  • low melting/boiling points
  • poor conductors of heat and electricity
41
Q

A more reactive halogen can (…) a less reactive halogen from an aqueous solution of its salt

A

displace

42
Q

A halogen can only displace another in what? (state of matter)

A

an aqueous solution

43
Q

Where are the transition metals in the periodic table?

A

In the central block

44
Q

Why do Group 7’s boiling points increase as you move down the group?

A

Because as you move down the group, formula mass increases

so intermolecular forces increase in strength

so more energy needed to overcome these intermolecular forces

45
Q

Why do Group 1’s melting/boiling points decrease as you move down the group?

A

As we go down group 1 the molecules increase in size (there are more energy levels)

So the metallic bonding decreases (is weaker) because the delocalised electrons are less attracted to the nucleus (weaker forces of attraction) as there is a greater distance between them

So take less energy to overcome/break these bonds

46
Q

3 out of 5 needed

Describe some observations when sodium reacts with water

A
  • effervescence / fizzing or bubbles or gas produced
  • sodium melts or turns into a ball
  • sodium moves (on the surface)
  • steam / mist / vapour is produced
  • sodium gets smaller / disappears
47
Q

2 out of 3

Describe what you would see when sodium reacts with chlorine

A

flame

(white) solid forms

colour of gas/chlorine disappears/fades