OCR GCSE C4 Revision – Flashcards

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When looking at the periodic table, Each row is a ............
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period
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When looking at the periodic table, each period starts with a very a.......... .......... in group 1 and ends with an b............. ........ in group 8
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a reactive metal

b unreactive gas

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When comparing the weights of atom, what do you use?
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Relative atomic mass
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When looking at the periodic table, what is a column called?
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A group
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Define a group
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a group of similar elements
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Give 5 properties of the alkali metals

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1. They are soft - can be cut easily with a knife

2. They are very reactive

3. They are not very dense - they float on water

4. They have one electron in their outer shell

5. They react with water

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When exposed to water, what do the alkali metals do?
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React to form an alkaline solution and hydrogen gas.
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Going down the group, do the alkali metals get more, or less reactive?
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More reactive
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Give 2 other names for energy levels
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shells

orbits

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What does the nucleas contain?
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Protons (+)

Neutrons (no charge)

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What do the energy shells contain?
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electrons (-)
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And atom is a........... it has b.... overall charge
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a neutral

b no

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Number of protons =
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number of electrons
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complete the table

Energy levels        max. number of electrons

 1                             a......

2                             b......

3                             c......

4                             d......

                                                           

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a 2

b 8

c 8

d the rest

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Why are the alkali metals in group 1?
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They all have 1 electron in their outer shells
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Why is potassium more reactive than lithium and sodium?
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Because the stray 1 elctron is in a higher energy level, meaning it's easier to get rid of - it is further away from the pull of the nucleas.
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How do the alkali metals try to get more stable?

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By losing the stray 1 electron
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Are the alkali metals good conducters of electricity?
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yes
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Do the alkali metals have a high melting point?
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No, they melt on a very gentle heat
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Most non-metals are ......
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molecular (e.g. O2 ,;N2 )
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All metals and C and Si are .........
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atomic (e.g. Na, Mg, Fe)
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Compounds of metals and no-metals are .........
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salts
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Many salts are ..................
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crystalline
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What happens when lithium (Li) is dropped into water?

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It floats, fizzes gently and dissapears as it turns into Lithium hydroxide (LiOH). It makes an alkali solution as it dissolves. It also gives off hydrogen gas.

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What happens when sodium (Na);is dropped into water?
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The reaction gives out enough energy to melt the sodium, it skates around the surface. More vigorous than lithium.

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Also produces sodium hydroxide (NaOH) and hydrogen.

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What happens when Potassium (K) is dropped into water?
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It floats and ignites with a lilac flame.

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Also produces potassium hydroxide (KOH) and hydrogen.

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How do you test for hydrogen?
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Collect gas and use a burning splint. It will give a squeeky pop if it's hydrogen.
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Will all salts dissolve in water?
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No, only some.
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Will solid salts conduct electricity?
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No, they must be dissloved first.

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Does pure H2O conduct electricity?
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No, it is the impurities in water that conduct electricity.
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What is the flame colour of Sodium (Na)?
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Yellow
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What is the flame colour of Potassium (K)?
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Lilac
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What is the flame colour of calcium (Ca)?
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Orange-red
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What is the flame colour of barium?
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Green
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What is the flame colour of copper (Cu)?
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Green
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What is a flame spectra? Explain it.
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When light given off by a flame is split into a spectrum, single pure colours can be seen.

 

Each element gives a unique flame spectra.

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Why are flame spectra different for each element?
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It's due to the electrons. The heat gives them energy, they move up to higher energy levels. They then lose energy and fall to a lower energy level. They give out energy in the form of light.

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Each atom has a different combination of ;jumps;, e.g. Hydrogen has 3 lines - 3 combinations of ;jumps;

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What is each line on a spectra?

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An electron falling down a level
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more electrons = ?
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more electrons = more lines in the spectra
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How was helium discovered?
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By analysing the spectrum of sunlight during an eclipse.
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In a balanced equation, is there any mass change?
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No, mass before = mass after

;;;;;;

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Inter- means
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between
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Intra- means
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within
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What happens when Chlorine (Cl2) is exposed to iron and heated?
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The iron wool must be heated initially, but one the reaction has started, heat from it keeps it going.

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There is an instant, vigorous reaction. Clouds of iron chloride form. Little iron is left.

;

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What happens when;Bromine (Br2) is exposed to iron and heated?
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It must be heated throughout the reaction. The reaction is slower than with chlorine, and less reactive. The iron wool is coated with iron bromide. Some doesn't react.
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What happens when Iodine (I2) is exposed to iron and heated?
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Strong heat is needed for a reaction. It's slow to react and only a small amount does react. Iron iodite is formed.

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Put the following in order of reactivity (most to least):

Bromine (Br2)

Iodine (I2)

Chlorine (Cl2)

;

;

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Chlorine (Cl2)

Bromine (Br2)

Iodine (I2)

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What is a danger of Chlorine (Cl2)?
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It's toxic
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What are the dangers of Bromine (Br2)?
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It's toxic and corrosive
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What is the danger of Iodine (I2)?
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It's harmful
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List 3 properties of Chlorine (Cl2)
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1. Dense, pale gas

2. Smelly and poisenous

3. occurs as chlorides, esp. sodium chloride in the sea

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List 3 properties of Bromine (Br2)
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1. Deep red liquid with red-brown vapour

2. Smelly and poisenous

3. Occurs as bromides, esp. magnesium bromide in the sea

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List 3 properties of Iodine (I2)
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1. Grey solid with purple vapour

2. Smelly and poisenous

3. Occurs as iodides and iodites in some rocks and in seaweed

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Define soluble
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can dissolve
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Why won't solid salts conduct electricity?
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Solid salts are made of ions held in place in a ;giant ionis; structure. They are held in place, dissolve/melt them and they will be free to move, allowing a current to flow.
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Define a cation
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a positive (+) ion
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Define an anion
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a negative (-) ion
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What happens when:

;;;;;; melt

Na+ Cl- ----------->

         disolve

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Na+          Cl-

+ ion               -ion 

Cation                 Anion

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Cations are attracted to the ..........
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Cathode
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Anions are attracted to the  ...........
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Anode
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Deinfe cathode
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negative eletrode
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Define anode
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Positive electrode
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At Cathode:

 

Na  +   e-   -------->

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Na
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At Anode

 

Cl-   -------->

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Cl + e-

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Why won't solid compunds made of ions conduct electricity?
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Because the ions are held in place. For charge to flow, the ions must be free to move.
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Why do group 1 element need to lose 1 electron?
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To have a full outer shell and be stable
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