Atomic Structure, Periodicity & Group 2
- Created by: amritabhakar__
- Created on: 26-03-18 19:13
What does the atomic number tell us about an element?
number of protons in an atom
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What letter represents mass number?
A
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How is mass number calculated?
mass number= number of protons + number of neutrons (total number of nucleons)
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Define relative atomic mass
Average mass of all isotopes of an element compared to 1/12 the mass of an atom of Carbon 12
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What are isotopes of an element?
Different forms of the same element, containing the same number of protons but different numbers of neutrons. They still have the same chemical properties
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Does 3d or 4s have a higher energy?
3d
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What is an orbital?
A region around the nucleus that can hold up to two electrons
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What would be the relationship between 2 electrons in the same orbital in terms of their spin?
Have opposite spin as they repel each other because they are both negative
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Explain why Chromium does not fit the trend for electronic configuration
It only has one electron in its 4s orbital before filling 3d
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Explain why copper does not fit the trend for electronic configuration
It only has one electron in its 4s orbital before filling 3d
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What are the two types of ionisation for a mass spectrometer? How do they differ?
1. Electron impact: electron gun (hot wire filament with current through its emitting electrons) knows off one electron from each particle to form 1+ molecular ions- these ions fragment
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What are the two types of ionisation for a mass spectrometer? How do they differ?
2. Electrospray: sample dissolved in volatile solvent and injected through a fine hypodermic needle to give am aerosol. Needle attached to positive terminal of a high-vol power supply and particles gain a proton from the solvent as they leave the nee
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When would you use the different types of ionisation in a mass spec?
Electron impact- organic or inorganic with low formula mass Electrpspray- substances with a higher moleculer mass including biological molecules
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Define first ionisation energy
Energy required to remove one mole of gaseous atoms to form one mole of gaseous 1+ ions
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Explain why this graph is this shape
1st ionisation increases across group 3 because of increased nuclear charge, decreased atomic radius and same electron shielding means more energy is needed to remove first electron.
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Explain the dips
Dip at Al: outer electron is in a 3p orbital which is higher energy than a 3s orbital so less energy needed to remove electron. Dip at S: one 3p orbital contains two electrons- repulsion between paired electrons and less energy to remove one
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What happens to the 1st ionisation as you go down group 2?
Decreases because number of filled electron shells decreases down the group- increased shielding. atomic radius so weaker force between nucleus and outer electron - less energy
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How does reactivity with water change as you go down group 2?
Increases because outer electrons are further from nucleus and there's more shielding so electrons are lost more easily
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Write an equation for the reaction of Barium and Water
Ba (s) +2H20 (l) ---> Ba(OH)2 (Aq) + H2 (g)
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Write an equation for the reaction of Magnesium and steam
Mg (s) + H2O (g) ----> MgO (s) + H2 (g)
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What is the rend io=n hydroxide solubility down group 2?
Increases down the group. Mg(OH)2 is almost insoluble. Ba(OH)2 creates a strong alkaline solution
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What is the trend in sulphate solubility down group 2?
Decreases down group. MgSO4 is soluble. BaSO4 is insoluble
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What is the trend in m.p down group 2?
decreases down group because sea of delocalised electrons is further from the positive charge of the nucleus so wekaer metallic bonds which takes less energy to breal
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What is the trend in atomic radius down group 2?
Increases as there are more occupied shells down the group
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Write the equations for the extraction of Titanium using Magnesium
TiO2 + 2Cl2 + C ----> TiCl4 + CO2
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What are flue gases?
Gases are produced by power stations which are harmful to the environment
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How can CaO or CaCO3 be used to remove flue gases?
CaCO3 (s) + SO2 (g) ---> CaSO3 (S) + CO2 (g)
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How can CaO or CaCO3 be used to remove flue gases?
Ca (s) + SO2 (g) ---> CaSO3 (s)
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What is Ca(OH)2 used for?
Used to neutralise soil: Ca(OH) (Aq) + 2HCl (aq) ---> 2H2O (l) + CaCl2 (aq)
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What is MG(OH)2 used for?
Milk of Magnesia- antacid to treat indigestion, heartburn, wind etc.
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What is a use of BaSO4? Why is it safe?
In Barium meals to outline gut in x-rays. Ba2+ is toxic but is fine as barium sulphate is insoluble
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How can BACl2 be used to test for sulfate ions?
Add to sample with HCl, white ppt will form if sulfate ions are present: Ba"+ + SO42- --> BaSO4
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Other cards in this set
Card 2
Front
What letter represents mass number?
Back
A
Card 3
Front
How is mass number calculated?
Back
Card 4
Front
Define relative atomic mass
Back
Card 5
Front
What are isotopes of an element?
Back
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