OCR GCSE C4 Revision – Flashcards
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Unlock answers| When looking at the periodic table, Each row is a ............ |
| period |
| When looking at the periodic table, each period starts with a very a.......... .......... in group 1 and ends with an b............. ........ in group 8 |
a reactive metal b unreactive gas |
| When comparing the weights of atom, what do you use? |
| Relative atomic mass |
| When looking at the periodic table, what is a column called? |
| A group |
| Define a group |
| a group of similar elements |
Give 5 properties of the alkali metals |
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 |
| When exposed to water, what do the alkali metals do? |
| React to form an alkaline solution and hydrogen gas. |
| Going down the group, do the alkali metals get more, or less reactive? |
| More reactive |
| Give 2 other names for energy levels |
shells orbits |
| What does the nucleas contain? |
Protons (+) Neutrons (no charge) |
| What do the energy shells contain? |
| electrons (-) |
| And atom is a........... it has b.... overall charge |
a neutral b no |
| Number of protons = |
| number of electrons |
complete the table Energy levels max. number of electrons 1 a...... 2 b...... 3 c...... 4 d......
|
a 2 b 8 c 8 d the rest |
| Why are the alkali metals in group 1? |
| They all have 1 electron in their outer shells |
| Why is potassium more reactive than lithium and sodium? |
| 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. |
How do the alkali metals try to get more stable? |
| By losing the stray 1 electron |
| Are the alkali metals good conducters of electricity? |
| yes |
| Do the alkali metals have a high melting point? |
| No, they melt on a very gentle heat |
| Most non-metals are ...... |
| molecular (e.g. O2 ,;N2 ) |
| All metals and C and Si are ......... |
| atomic (e.g. Na, Mg, Fe) |
| Compounds of metals and no-metals are ......... |
| salts |
| Many salts are .................. |
| crystalline |
What happens when lithium (Li) is dropped into water? |
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. |
| What happens when sodium (Na);is dropped into water? |
The reaction gives out enough energy to melt the sodium, it skates around the surface. More vigorous than lithium. ; Also produces sodium hydroxide (NaOH) and hydrogen. |
| What happens when Potassium (K) is dropped into water? |
It floats and ignites with a lilac flame. ; Also produces potassium hydroxide (KOH) and hydrogen. |
| How do you test for hydrogen? |
| Collect gas and use a burning splint. It will give a squeeky pop if it's hydrogen. |
| Will all salts dissolve in water? |
| No, only some. |
| Will solid salts conduct electricity? |
No, they must be dissloved first. |
| Does pure H2O conduct electricity? |
| No, it is the impurities in water that conduct electricity. |
| What is the flame colour of Sodium (Na)? |
| Yellow |
| What is the flame colour of Potassium (K)? |
| Lilac |
| What is the flame colour of calcium (Ca)? |
| Orange-red |
| What is the flame colour of barium? |
| Green |
| What is the flame colour of copper (Cu)? |
| Green |
| What is a flame spectra? Explain it. |
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. |
| Why are flame spectra different for each element? |
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. ; Each atom has a different combination of ;jumps;, e.g. Hydrogen has 3 lines - 3 combinations of ;jumps; |
What is each line on a spectra? |
| An electron falling down a level |
| more electrons = ? |
| more electrons = more lines in the spectra |
| How was helium discovered? |
| By analysing the spectrum of sunlight during an eclipse. |
| In a balanced equation, is there any mass change? |
No, mass before = mass after ;;;;;; |
| Inter- means |
| between |
| Intra- means |
| within |
| What happens when Chlorine (Cl2) is exposed to iron and heated? |
The iron wool must be heated initially, but one the reaction has started, heat from it keeps it going. ; There is an instant, vigorous reaction. Clouds of iron chloride form. Little iron is left. ; |
| What happens when;Bromine (Br2) is exposed to iron and heated? |
| 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. |
| What happens when Iodine (I2) is exposed to iron and heated? |
Strong heat is needed for a reaction. It's slow to react and only a small amount does react. Iron iodite is formed. |
Put the following in order of reactivity (most to least): Bromine (Br2) Iodine (I2) Chlorine (Cl2) ; ; |
Chlorine (Cl2) Bromine (Br2) Iodine (I2) |
| What is a danger of Chlorine (Cl2)? |
| It's toxic |
| What are the dangers of Bromine (Br2)? |
| It's toxic and corrosive |
| What is the danger of Iodine (I2)? |
| It's harmful |
| List 3 properties of Chlorine (Cl2) |
1. Dense, pale gas 2. Smelly and poisenous 3. occurs as chlorides, esp. sodium chloride in the sea |
| List 3 properties of Bromine (Br2) |
1. Deep red liquid with red-brown vapour 2. Smelly and poisenous 3. Occurs as bromides, esp. magnesium bromide in the sea |
| List 3 properties of Iodine (I2) |
1. Grey solid with purple vapour 2. Smelly and poisenous 3. Occurs as iodides and iodites in some rocks and in seaweed |
| Define soluble |
| can dissolve |
| Why won't solid salts conduct electricity? |
| 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. |
| Define a cation |
| a positive (+) ion |
| Define an anion |
| a negative (-) ion |
What happens when: ;;;;;; melt Na+ Cl- -----------> disolve |
Na+ Cl- + ion -ion Cation Anion |
| Cations are attracted to the .......... |
| Cathode |
| Anions are attracted to the ........... |
| Anode |
| Deinfe cathode |
| negative eletrode |
| Define anode |
| Positive electrode |
At Cathode:
Na+ + e- --------> |
| Na |
At Anode
Cl- --------> |
Cl + e- |
| Why won't solid compunds made of ions conduct electricity? |
| Because the ions are held in place. For charge to flow, the ions must be free to move. |
| Why do group 1 element need to lose 1 electron? |
| To have a full outer shell and be stable |
