Periodic table And Energy Module3 AS Flashcards
What happens to the reactivity of group 17 halogens as you go down the group
It decreases as increased atomic radius and more electron shielding thus harder to gain man electron as nuclear attraction decreases
What are the advantages and disadvantages of using chlorine
Advantage: Kills Bacteria
Disadvantage: Forms Toxic Compounds
What forms when a halogen reacts with NAOH and what are the conditions?
Salt + Chromate Solution + Water
Conditions: Cold and Solid NaOH
What is a displacement reaction
When a more reactive elements displaces a less reactive one in a solution
What colour does Potassium Iodide form when displaced
Brown
What colour does Potassium Bromide form when displaced
Yellow
What colour does Potassium Chloride form when displaced
Green
What otganic solvent colour does Iodine form when displaced
Purple
What organic solvent colour does Bromine form when displaced/reacts with thyself
Yellow
What colour does chlorine form when displaced/reacts with thyself
Colourless
How would you test for carbonates
Add Dilte HCL in a test tube and if Effervescence/bubbling occurs, it indicates the prescence of carbonate as CO2 is produced when carbonate reacts w/ HCL and to confirm it, bubbling the gas through limewater through a delivery tube and if it turns milky/cloud, it confirms the prescence of CO2
How would you tes for sulfates
Add Dilute HCL and Barium Chloride and if sulfates present, a white precipitate shall form
How would you test for halide ions
Add dilute HCL and nitric acid and silver nitrate
SIlver chloride is white
Silver bromide is cream
Silver iodide is yellow
How would you confirm prescence of those halide ions
Chlorine dissolves in DILUTE ammonia
Bromine dissolves in CONCENTRATED ammonia
Iodine does not dissolve in any…
How would you test for ammonium ions
Warm with NaOH but not ammonia to generate ammonia gas and put it through litmus paper, which will turn it blue
State the ionic equation for a displacement reactions between chlorine and bromine
2Br- (in the solution) and Cl2(elemental) –> 2Cl- + Br2
What is the defenition of First Ionisation Energy
Amount of energy required to remove 1 mol. of electrons from 1 mol. of gaseous atoms
Why does tne boiling point increase across a period for elemtns w/ metalic bonds
More electrons across the group thus more electrons become delocalised thus more metalic bonds form forming stronger metalic bonds whioch require more energy to overcome and size of atom increases
Why can magnesium bromide conduct electricity in aqueous state but not in solid
In aqueous: Ions are mobile and free to move aroud the structure carrying chargw
In Solid: Ions are fixed in position in a lattice
Why does magnesium bromide have a high melting point
As it is a giant ionic lattice containing strong electrosatic bonds between oppositely charged ionswhich require a lot of energy to overcome
Why does the first ionisation energy of boron decrease going from berillium to boron
As a new sub shell is being filled –> 1s2 2s2 sp1, thus it requires less energy to lose an elec
Why does the first ionisation energy decrease going from nitrogen to oxygen
As oxygen has an orbital where it has a pair of electrons which repel eachother thus it is easier to lose an electron
What happens to the atomic radius across a period
N. of protons across a group , positive charge of nucleus becomes LARGER AND INCREASING NUCLEAR CHARGE thus nuclear attraction increases and n. of shells stay present so electron shielding remains constant thus atomic radius decreases
Why does reactivity increase going down group 2
As elec. shielding increases down the group thus nuclear attraction decreases thus easier to lose an electron
What is the group 2(Mg) reaction with water
Mg + H20 –> 2MgO + H2
What is the Group 2(Mg) reaction with Oxygen
2Mg + O2 –> 2MgO
What is the group 2 reaction with dilute acids (H2S04)
Mg + H2S04 –> MgSO4 + H2
What is the reaction between group 2 oxides and water
MgO and H20 –> Mg(OH)2
What are the 2 uses of Group 2 Oxides
Used to neutralise acid soils
Used in some indigestion tablets – antacticds
What type of atom does LDF occur between
Between Molecules
What type of structure are metals
Giant lattices
What does it mean if an element has a high first ionisation energy
It means that it is Harder to lose elec.
means that it has greater nuclear attraction and low elec. shielding and small atomic radius
How does sulfur Phosphorous and chlorien exist
SUlfur – S8
Phosphorous - P4
Chlorine - Cl2
Why does sulfur phosphorous and chlorine not conduct elec.
As they have no free elc as theyre in S8 P4 etc.
How does metalic bonding occur
As there is nuclear charge in metals due to the electrons in outer shell thus the nuclear charge causes attraction between oppositely charged ions
Write ionic equation for carbonates
CO3 2- + 2H+ –> CO2 + H20
Write ionic equation to test for halide ions
Ag+ + Br- –> AgBr
Write ionic equation for sulfates
SO4 2- + Ba 2+ –> BaSO4
Write equation between aqueous sodium chlorate and hydrochloric acid
NaClO + 2HCl -> NaCl + Cl2 + H20
Why is second ionisation energy greater than first
As second electron removed from a CATION -> Greater nuclear attraction
