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IGCSE Chemistry- Part 2 > The periodic table > Flashcards

Flashcards in The periodic table Deck (58):
1

where are metals and non-metals in the periodic table?

from left to right across the periodic table there is a gradual change from metal to non-metal

2

how are elements classified as metal and non-metal?

- if an element is electrically conductive and its oxide is basic, then it's a metal
- If an element is non electrically conductive and its oxide is acidic, then its a non-metal

3

what are metals?

metals are all conductors and they form metal-oxides, which are alkaline

4

what are non-metals?

non-metals don't conduct and they form non-metal oxides, which are acidic

5

what happens when magnesium reacts with oxygen?

magnesium burns with a bright, white flame to form a white ash of magnesium oxide

6

what happens when carbon reacts with oxygen?

carbon burns with a yellow/orange flame to form a colourless gas: co2

7

what happens when sulfur reacts with oxygen?

sulfur burns with a blue flame to form a colourless gas

8

why do elements in the same group have similar chemical properties?

because they have the same number of electrons in their outer shell

9

what is the role of the electrons in the outermost shell?

the electrons in the outermost occupied cell determine the chemical properties of the atom; it is called the valence shell

10

what are the noble gases?

group 8/0 are called the noble gases. These elements do not form compounds with other elements

11

what does inert mean?

chemically unreactive

12

why are noble gases not reactive?

they do not react because they have a full outer shell in each atom, which makes them stable. Having a full outer shell means they do not need to gain, or lose electrons.

13

what happens when group 1 elements react with water?

group 1 elements react vigorously with water to give an alkaline solution of the metal hydroxide as well as hydrogen gas.

14

what changes as you go down the elements in a group?

the elements are more reactive

15

what happens when lithium reacts with water?

- moves around the surface of the water
- hissing sound
- bubbles of gas
- gets smaller and smaller; eventually disappears

16

what happens when sodium reacts with water?

- moves around the surface of the water
- hissing sound
- bubbles of gas
- melts into a shiny ball
- gets smaller and smaller; eventually disappears

17

what happens when potassium reacts with water?

- moves around the surface of the water
- hissing sound
- bubbles of gas
- melts into a shiny ball
- burns with a lilac-coloured flame
- gets smaller and smaller; eventually disappears

18

what trends can we see from the reactions of the elements in group 1?

the further down the group we get, the more reactive the elements are

19

why does reactivity increase down group 1?

as you go down group 1, the number of electron shells increases. Lithium has 2 sodium has 3 etc. Therefore, the outermost electron gets further away from the nucleus. The attraction from the positive nucleus and the negative electron is less. This makes it easier to remove the electron and makes the atom more reactive

20

what colour and physical state is chlorine at room temperature?

chlorine is a gas at room temperature and is pale green

21

what colour and physical state is bromine at room temperature?

bromine is a liquid at room temperature and is red/brown

22

what colour and physical state is iodine at room temperature?

iodine is a solid at room temperature and is black/dark grey

23

what is group 7?

the halogens

24

what happens to reactivity as you go down group 7?

reactivity decreases as we go down the group because of the increasing size of the atoms. The outer shell gets further away from the nucleus and the attraction between the nucleus and the electrons gets bigger, so an electron is less easily gained

25

what do halogen atoms do?

a halogen atom is able to attract an extra electron into its outermost shell to make eight electrons in total. It is the nucleus of each atom that attracts the extra electron

26

what properties would we expect to change as we go down the halogens?

we would expect the colour to go darker and the melting and boiling points to keep getting higher

27

what is the difference between hydrogen chloride gas and hydrochloric acid?

- hydrogen chloride, HCl, is a colourless gas at room temperature. It dissolves in both water and many organic solvents like methylbenzene
- Hydrochloric acid is HCl dissolved in water, then the two ions H+ and Cl- become detached, leaving the acidic H+, this is why it is an acid

28

what is the meaning of ionise?

convert into an ion or ions, typically by removing one or more electrons

29

what is methylbenzene?

a chemical name for toluene, it is a colourless water-insoluble liquid

30

why is hydrogen chloride acidic in water but not in methylbenzene?

- hydrogen chloride is dissolved in water, it dissociates (basically, just splits up) to form H+ ions which are responsible for its acidic properties. The molecules ionise when dissolved in water
- when hydrogen chloride is dissolved in methylbenzene it doesn't dissociate or ionise, so it doesn't form H+ ions so it is not acidic

31

describe an experiment to demonstrate that a more reactive halogen will displace a less reactive halogen from a solution of one of its salts?

chlorine is more reactive than bromine (above bromine in group 7). Sodium bromine is a salt of bromine that will dissolve in water. So chlorine will displace bromine from sodium bromide solution. This means that if chlorine (as gas or dissolved in water) is added to sodium bromide solution, bromine forms and the mixture turns brown. We say that bromine has been displaced from sodium bromide.

32

what does displaced mean?

a chemist's word for pushed out

33

what happens to the halogens in a displacement reaction?

the more reactive halogen is reduced (gains electrons) and the less reactive halogen is oxidised (loses electrons)

34

what is a redox reaction?

a reaction in which both reduction and oxidation take place

35

what is OILRIG?

Oxidation
Is
Loss
Reduction
Is
Gain

36

what is the order of the reactivity series?

potassium
sodium
calcium
magnesium
aluminium
carbon
zinc
iron
tin
lead
hydrogen
copper
silver
gold
platinum

37

how can reactions with water and dilute acids be used to deduce order of reactivity?

the higher up in the series the metal is, the more vigorously it will react with other elements

38

how can you deduce the position of a metal within the reactivity series between metals and their oxides?

if you set up an experiment with a metal oxide or a metal salt dissolved in water, then introduce a more reactive metal, it will displace the current one. Introduce a less reactive metal and no displacement will take place. From this you can deduce which metals are more and less reactive

39

what is oxidation?

the gain of oxygen

40

what is reduction?

the loss of oxygen

41

what is a oxidising agent?

a substance in that is capable of oxidising another substance. Causes the other substance to lose its electrons, while it gains them

42

what is a reducing agent?

a substance in that is capable of reducing another substance. Causes the other substance to gain electrons, while it loses its own

43

what is rusting?

a chemical reaction between iron, water and oxygen

44

what conditions does iron rust in?

rusting only occurs when iron is in contact with both water and oxygen (air).

45

what is happening when iron rusts?

the chemical reaction that is taking place is oxidation of iron to form ion oxide (oxidation reaction), water then bonds to the iron oxide and forms hydrated iron oxide-rust

46

what are the word equations for rusting?

- iron+oxygen=iron oxide
- iron oxide+water=hydrated iron oxide

47

what makes rusting faster?

rusting takes place faster if there are electrolytes such as sodium chloride in the water. NaCl is present in sea water

48

how can rusting be prevented?

- grease (nuts and bolts)
- oil (bicycle chain)
- paint (car body)
- plastic
- galvanising (steel frames)

49

how do things stop rusting?

because they stop oxygen or water from reaching the surface of the metal

50

what is galvanising?

a method of rust prevention. The iron or steel object is coated in a thin layer of zinc. This stops oxygen and water from reaching the metal underneath- but the zinc also acts as a sacrificial metal. Zinc is more reactive than iron, so it oxidises in preference to the iron object.

51

what are sacrificial metals?

magnesium and zinc are often used as sacrificial metals. They are more reactive than iron and lose their electrons in preference to iron.

52

what is the sacrificial protection of iron?

the sacrificial method involves placing a more reactive metal (such as zinc) with the iron. Water and oxygen then react with the sacrificial metal rather than the iron (as its more reactive than the iron)

53

how does tin prevent rusting?

tin is used to coat things like steel cans, it does not act as a sacrificial metal. It acts only as a barrier to stop air and water reaching the surface of the iron or steel. The tin layer may actually make rusting happen faster if it gets scratched, because then iron loses electrons in preference to tin.

54

what happens when magnesium reacts with dilute hydrochloric and dilute sulfuric acid?

- bubbles of gas
- magnesium disappears
- reaction mixture gets hot
- colourless solution is formed

55

what happens when aluminium reacts with dilute hydrochloric and dilute sulfuric acid?

- slow to start reacting when cold, but bubbles form when heated
- aluminium disappears
- colourless solution formed

56

what happens when zinc reacts with dilute hydrochloric and dilute sulfuric acid?

- bubbles of gas
- zinc disappears
- colourless solution formed

57

what happens when iron reacts with dilute hydrochloric and dilute sulfuric acid?

- bubbles of gas
- iron disappears
- pale green solution formed

58

what does dilute mean?

make a liquid thinner or weaker by adding water or another solvent to it