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