C1 - Atomic Structure & Periodic Table Flashcards
Complete the relative mass and charge numbers of the 3 subatomic particles
Proton - 1 mass, +1 charge
Neutron - 1 mass, 0 charge
Electron - 0 mass, -1 charge
What determines the size of an atom?
The volume of the electrons’ orbits
23 - the atomic (proton) number
Na TRUE OR FALSE?
11 - the (relative atomic) mass number
False - they are the other way around.
The relative atomic mass number is the top one
The atomic number is the bottom one
What do these tell you about an element:
a) The relative atomic mass number
b) The atomic number
a) The sum of protons and electrons
b) The amount of protons or electrons
Which subatomic particle determines the element?
a) Protons
b) Neutrons
c) Electrons
a) Protons - once this number changes, the element changes
What is it that makes isotopes different?
The amount of neutrons the element has, e.g
Carbon 12 has 6 neutrons, Carbon 13 has 7 neutrons
The 12/ 13 refers to their top number (the mass number)
What is the formula for relative atomic mass?
Sum of abundance of all the isotopes
Copper has 2 stable isotopes. Cu-63 has an abundance of 69.2% and Cu-65 has an abundance of 30.8%. Calculate the relative atomic mass of copper to 1 decimal place
ANSWER - 63.6
69. 2 x 63) + (30.8 x 65
- ———————————–
69. 2 + 30.8
What does abundance mean?
Amount
What is the difference between mixtures and compounds?
Compounds are when elements react together, mixtures are just when their held together, but aren’t chemically combined - they are easily separated (without need of a chemical reaction to separate them like compounds need)
Give the definition of a compound
Substances formed from 2 or more elements, the atoms of each are in fixed proportions throughout the compound and held together by chemical bonds
Are the nuclei affected when atoms bond?
No - only the electrons
What is ionic bonding?
A compound formed between a metal and a non-metal consists of ions. The metal atoms lose electrons to form positive ions, and the non-metal atoms gain electrons to form negative ions. The opposite charges means their strongly attracted to each other.
OPPOSITE CHARGES
ATTRACT
Give some examples of ionically bonded substances and covalently bonded substances
IONIC - Sodium chloride IONIC - Magnesium oxide IONIC - Calcium oxide COVALENT - hydrogen chloride gas COVALENT - carbon monoxide COVALENT - water
What is covalent bonding?
A compound formed from non-metals consists of molecules. Each atom shares an electron with another atom.
What are these compounds?
a) NH3
b) H2SO4
c) CaCl2
d) Na2CO3
e) HCl
f) CH4
g) C6H12O6
a) Ammonia
b) Sulfuric acid
c) Calcium chloride
d) Sodium carbonate
e) Hydrochloric acid
f) Methane
g) Glucose
Balance the equation:
H2SO4 + NaOH = Na2SO4 + H2O
H2SO4 + 2 NaOH = Na2SO4 + 2 H2O
Give an example of a mixture
Air
Crude oil
The properties of a mixture are just a mixture of the properties of the separate parts - the chemical properties of a substance aren’t affected by it being part of a mixture. True or false?
True - Stuff still reacts with parts in the air even if it’s with other stuff too
Explain why you shouldn’t use a pen to draw a line on the filter paper in chromatography (1 mark)
The pen ink may dissolve in the solvent and rise in the filter paper
Put this in the correct order of the method for paper chromatography:
1) Place a lid on the container to stop the solvent from evaporating
2) Make sure the ink isn’t touching the solvent - you don’t want it to dissolve
3) The end result is a pattern of spots called a chromatogram
4) Draw a line in pencil near the bottom of a sheet of filter paper
5) If any dyes in the ink are insoluble in the solvent you used, then they’ll stay on the baseline
6) Add a spot of ink to the line and place the sheet in a beaker of solvent (such as water)
7) The solvent used depends on what’s being tested. Some compounds dissolve well in water, but sometimes other solvents (like ethanol) are needed
8) The solvent seeps up the paper, carrying the ink with it
9) Each different dye in the ink will move up the paper at a different rate so they will separate. Each dye will form a spot in a different place - 1 spot = 1 dye
10) When the solvent has nearly reached the top of the paper, take it out and leave it to dry
4) Draw a line in pencil near the bottom of a sheet of filter paper
6) Add a spot of ink to the line and place the sheet in a beaker of solvent (such as water)
7) The solvent used depends on what’s being tested. Some compounds dissolve well in water, but sometimes other solvents (like ethanol) are needed
2) Make sure the ink isn’t touching the solvent - you don’t want it to dissolve
1) Place a lid on the container to stop the solvent from evaporating
8) The solvent seeps up the paper, carrying the ink with it
9) Each different dye in the ink will move up the paper at a different rate so they will separate. Each dye will form a spot in a different place - 1 spot = 1 dye
5) If any dyes in the ink are insoluble in the solvent you used, then they’ll stay on the baseline
10) When the solvent has nearly reached the top of the paper, take it out and leave it to dry
3) The end result is a pattern of spots called a chromatogram
What does soluble mean?
Able to dissolve in water. The opposite of this is insoluble - where it cannot dissolve in water
Give the name of the pattern of dots created at the end of chromatography
A chromatogram
Which method of separation should be used to separate:
a) Insoluble solids from liquids
b) soluble solids from solutions
c) liquids
d) solutions (both the soluble solid and the liquid at the end)
a) Filtration (filter paper)
b) Evaporation or Crystallisation
c) Fractional distillation
d) Distillation
What is the method for the separating technique of crystallisation?
1) Pour the solution into an evaporating dish and gently heat. Some will evaporate and the solution will beome more concentrated
2) Once some of the solvent has evaporated or when crystals start to form, remove the heat and let it cool
3) The salt should start to form crystals as it becomes insoluble in the cold, highly concentrated solution
4) Filter the crystals from the solution, and leave them to dry in a warm place (a drying oven or desiccator)
Give the method for the separation technique of evaporation
1) Pour the solution in an evaporating dish
2) Slowly heat the solution (with a bunsen burner, water bath or electric heater). The solvent will evaporate and the solution will become more concentrated. Eventually, crystals will begin to form
3) Keep heating the evaporating dish until only dry crystals are left - the soluble solid from the solution as all the water has evaporated
Why would you have to use crystallisation instead of evaporation?
If the salt decomposes when heated, then crystallisation is necessary
What can be used to separate rock salt (a mixture of salf and sand?
Filtration and evaporation (crystallisation if you want larger crystals), as water can be added, the sand filtered out then the salt water solution evaporated/ crystallised.
What is distillation used for?
Simple distillation is used to separate solutions
Fractional distillation is used to separate a mixture of liquids
Talk through the basic steps of distillation
1) The solution is heated
2) Part of solution with a lower boiling point evaporates first
3) Vapour cools & condenses in the condenser/ cooling column, and is collected
4) The rest of the solution (the solid, if it’s sea water) gets left in the flask
5) Pure liquid is collected at the other end once it leaves the cooling tube thing
How does the basis for fractional distillation work?
It separates the liquids based on their boiling points - with simple distillation it will only work if the boiling points aren’t close together
Where is the coolest part of the column in distillation?
The top - as it is furthest from the heat
In the condensing tube/ condenser, which way does the water go in and out?
WATER OUT ^
WATER IN ^
They both go upwards
Complete the sentence:
In fractional distillation, the liquid with the highest boiling point…
Either remains in the flask or gets separated last
Fill the blanks:
With __________ distillation, liquids with higher _______ points might also start to _________ early on. But the column is ______ towards the top, so they will only get part way up before __________ and running back down to the _____ again.
Fractional Boiling Evaporate Cooler Condensing Flask
What is the fractionating column?
It goes on top of the flask, and is filled with glass rods for some reason.
One no more of the first liquid produced by fractional distillation is produced, how do you start to separate the next liquid in the mixture?
You raise the temperature until the next liquid reaches the condenser
John Dalton said what about atoms at the start of the 19th century?
That they were solid spheres - plum pudding model not belief back then
Who concluded that atoms must have electrons due to his measurements of charge and mass?
J J Thompson - 1897
The plum pudding model shows the atom as a ball of positive charge with electrons in it. True or false?
True - after electrons were discovered in 1897 by J J Thompson
Who discovered these subatomic particles and in what Order?
1) Electrons - J J Thompson
2) Protons - Ernest Rutherford
3) Neutrons - James Chadwick
How did Ernest Rutherford disprove the plum pudding model?
He fired alpha particles at a thin sheet of gold expecting them to go straight through or deflect a little, because the positive charge was thought to be very spread out through the atom. But this did not happen, so he invented the nuclear model of the atom - the positvely charged nucleus at the centre and a negative “cloud” of electrons surrounding it (so most of the atom is empty space).
When alpha particles came near the concentrated, positive charge of the nucleus, they were deflected. When the nucleus collided, they were deflected backwards. Otherwise, they passed through the empty space
What did Bohr change to Rutherford’s nuclear model of the atom?
Instead of it being a cloud of negative charge caused by the electrons, he suggested that electrons orbit in fixed shells.
What is the modern model of the atom known as?
The nuclear model
Fill the blanks:
Further experiments by Ernest __________ and others showed that the nucleus can be _______ into smaller particles, each with the same ______ as a ________ _______. These subatomic particles were named _______
Rutherford Divided Charge Hydrogen nucleus Protons
Who discovered neutrons?
James Chadwick, around 20 years after scientists accepted the existence of nuclei in atoms
What are the 5 electron shell rules? (with these hints)
1) What electrons do
2) The lowest energy levels
3) Amount of electrons
4) Happy atoms
5) Why atoms react
1) Electrons always occupy shells (sometimes called energy levels)
2) The lowest energy levels are always filled first - these are the ones closest to the nucleus
3) Only a certain number of electrons are allowed in each shell - 1st shell has 2 electrons, 2nd shell on has 8 electrons
4) Atoms are happier when they have full electron shells (like the noble gases in group 0/8)
5) In most atoms, the outer shell is not full and this makes the atom want to react to fill it.
Up to what point do atoms’ shells become diffcult to draw?
After the 20th element
Hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, neon, sodium, magnesium, aluminium, sillicon, phosphorus, sulfur, chlorine, argon, potassium and calcium
How were elements arranged in the early 1880’s? What was the problem with this?
How are they arranged now?
By atomic mass - did not consider their properties
By atomic number now (after electrons and protons discovered - 20th century)
What is atomic mass?
The average mass of one atom of an element
When and how did Mendeleev arrange his Table of Elements?
1869.
He mainly put elements in order of atomic mass, but switched the order if the properties meant it should be changed. There were also gaps to make sure that elements with similar properties stayed in the same groups (also, they indicated undiscovered elements)
When were isotopes discovered?
a) 19th century
b) 20th century
c) 21st century
b) 20th century - confirmed Mendeleev was right in considering properties when organising elements
In the periodic table:
a) the further across you go…
b) metals are on the…
c) elements with similar properties form…
d) all group 1 elements are…
e) elements react more vigorously as you go…
f) the rows are called…
g) these represent
a) the more protons are there
b) left & bottom - 2 elements), and non metals are on the right (more metals)
c) columns called groups
d) metals and react similarly
e) down the groups
f) periods
g) another full shell of electrons
Non metals form positive ions when they react, metals form negative ions when they react. True or false?
False - usually non-metals form negative ions, metals form positive atoms
Fill the blank:
Metals to the left of the electronic table don’t have as many electrons to remove compared to the metals…
Towards the bottom of periodic table (as they have electrons a long way from the nucleus so feel a weaker attraction)
Both these effects mean not much energy is needed to remove the electrons, so it’s possible for the elements to react and form positive ions with a full outer shell
If an atom loses electron, what is the charge?
Positive overall - it becomes a positive ion
How do non-metals generally complete their full outer shell? Why is it s difficult for them to become positive ions?
By either sharing or gaining electrons.
Because they have lots of electrons they need to lose to become a positive ion
What are 3 similar and basic properties of metals that have metallically bonded?
They’re strong (hard to break) but malleable
They’re great at conducting heat and electricity
They have high boiling and melting points
Non metals form a variety of different structures, so…
They have a wide range of chemical properties
As non-metals don’t have metallic bonding, what properties do they OFTEN/ GENERALLY show when they bond?
They are dull looking More brittle Aren't always solids at room temperature Don't conduct electricity Lower density
What are group 1 elements? (a few words)
Name some
Reactive, soft metals
Alkali metals - lithium, sodium, potassium, rubidium, caesium and francium
What makes Alkali metals so reactive? Which are more reactive?
Group 1 metals have only 1 electron on their outer shell, so they are very reactive and have similar properties.
The further down the column you go, the more reactive they become because the shells get further away from the nucleus, so more likely to react (sodium i less reactive than caesium)
Name some trends as you go down the group 1 column.
Increase in reactivity (outer electron is more easily lost)
Lower melting & boiling points
Higher relative atomic mass
What do alkali metals form when they react with non metals?
Ionic compounds - generally white solids that dissolve in water to form colourless solutions
What is produced when group 1 elements react with water?
Hydrogen, the energy given out when they react increases as you go down the group (for potassium & below, there’s enough to ignite hydrogen - why a lilac flame is seen when potassium experiment occurs)
Also, they form hydroxides that dissolve in water to give alkaline solutions
Balance this equation, and what experiment this is:
Na(s) + H2O(l) = NaOH(aq) + H2(g)
2Na + 2H2O = 2NaOH + H2
Sodium + water = Sodium hydroxide + hydrogen
Putting a group 1 element in water (the sodium can be replaced with any alkali metal and it would be the same)
What will reacting a group 1 element with chlorine produce?
A salt (group 1 metals react vigorously when heated in chlorine gas to form white salts called metal chlorides)
THINK NaCl!
What happens when a group 1 element reacts with oxygen?
It will form a metal oxide, different depending on the metal used:
Lithium reacts to form lithium oxide (Li2O)
Sodium reacts to form a mixture of sodium oxide (Na2O) and sodium peroxide (Na2O2)
Potassium reacts to form a mixture of potassium peoxide (K2O2) and potassium superoxide (KO2)
What are group 7 elements known as? Give a few words to describe them, and name some
Halogens - all non-metals with coloured vapours.
Fluorine, chlorine, bromine, iodine
(all those examples are poisinous too, dunno about astatine)
All halogens exist as pairs of atoms. True or false?
True - F2, Cl2, Br2 I2 etc
Give some qualities of:
a) Fluorine
b) Chlorine
c) Bromine
d) Iodine
a) Very reactive, poisonous yellow gas
b) Fairly reactive, poisonous dense green gas
c) Dens, poisonous, red-brown volatile liquid
d) Dark grey crystalline solid or a purple vapour (has poison symbol too, so…)
As you go down the group, what are some qualities of the group 7 elements?
Become less reactive (harder to gain one more electron as the outer shell is far away
Higher melting and boiling points
Higher relative atomic masses
What can halogens form?
Molecular compounds - they share electrons in covalent bonding with other non-metals. The compounds that form when halogens react with non-metals all have simple molecular structures
Halogens form what type of bond with metals?
a) Compound
b) Ionic
c) Metallic
b) Ionic - the halogens form 1- ions called halides. The compounds that form have ionic structures
I think, they only/mostly do this with group 1 metals
Complete the sentence:
Reactive halogens will displace…
less reactive ones
e.g. chlorine can displace bromine and iodine from an aqueous solution of its salt. Bromine will also displace iodine because of the trend in reactivity (whatever that means)
Give a few words to describe group 0 elements, then name a few
Noble gases are all inert, colourless gases.
Helium, neon, argon, krypton, xenon, radon
Give some qualities of group 0 elements as you go down their column
The boiling points increase (increase in electron amounts, greater intermolecular forces between them)
Increasing relative atomic mass
What does monatomic gases mean? Which group does this this apply to?
Group 0 - Single atoms not bonded to each other
What are all group 0 elements at room temperature?
Colourless gases
Noble gases are flammable - true or false?
False - they won’t set on fire as they are inert (as they have complete shells)
Exam questions:
1) Does xenon or neon have a higher boiling point? (1 mark)
2) Argon is not very reactive. Use your knowledge of its electronic structure to explain why (2 marks)
1) xenon (because it is further down the column)
2) Argon has a full outer shell (1 mark)
So it’s electronically stable and does not readily lose or gain electrons (1 mark)
