Unit 1.6 - Periodic Table Flashcards
1) What does the group number tell you?
2) What does the period number tell you?
3) What block are the transition metals in?
1) Number of electrons in outer shell.
2) Number of quantum shells containing electrons.
3) D block
When was the periodic table produced?
Mendeleev in 1869.
What is periodicity?
Name given to any pattern in physical or chemical properties that appears across a period.
State the order of bond strength.
Giant covalent > metals > simple molecular
Why does metallic bonding have a higher boiling point than melting point?
Liquid state but atoms are separated to distances forming the vapour and this involves breaking of metallic bonds.
2nd period - State the type of structure in:
1) Li and Be
2) B and C
3) N, O and F
4) Ne
1) Giant metallic
2) Giant covalent
3) Simple covalent
4) Simple atoms
3rd period - State the type of structure in:
1) Na, Mg and Al
2) Si
3) P, S and Cl
4) Ar
1) Giant metallic
2) Giant covalent
3) Simple covalent
4) Simple atoms
1) What is atomic radius?
2) What method is used to determine atomic radii?
1) Measure of size of atoms in crystals and molecules.
2) X-ray diffraction.
1) What is the trend in atomic radii across a period?
2) Explain why.
1) Atomic radii decrease across period.
2) Increase in nuclear charge, no increase in electron shielding and increase in effective nuclear charge.
1) What is the trend in atomic radii down any group?
2) Explain why.
1) Increases down any group.
2) Number of electron shells increases.
1) What is the trend in 1st ionisation energy across a period?
2) Explain why.
1) Increases across period.
2) Increase in nuclear charge in same energy level, little extra shielding and greater attraction between nucleus and outer electrons.
1) What is the trend in 1st ionisation energy down a group?
2) Explain why.
1) Decreases down group.
2) Increase in nuclear charge, increase in electron shielding and decrease in effective nuclear charge.
Electronegativity
Ability of an atom to attract a shared pair of electrons towards itself in a covalent bond.
1) What is the trend in electronegativity across a period?
2) Explain why.
1) Increases across period.
2) Increase in nuclear charge, no increase in electron shielding and increase in effective nuclear charge.
1) What is the trend in electronegativity down a group?
2) Explain why.
1) Decreases down each group.
2) Increase in nuclear charge, increase in electron shielding and decrease in effective nuclear charge.
1) What happens to an element when oxidation number increases?
2) What happens to an element when oxidation number decreases?
1) Lost electrons - Oxidised
2) Gained electrons - Reduced
Describe observations when:
1) Lithium reacts with water
2) Sodium reacts with water
3) Potassium reacts with water
1) Floats, moves slowly, effervescence and fizzing sound.
2) Faster, effervescence and orange spark.
3) More reactive, lilac burning flame and vigorous effervescence.
1) State and explain the general trend in reactivity of group 1 and 2 down the group.
2) Why do group 1 melt with cold water but group 2 don’t?
1) Increases down group - nuclear charge increases, increase in electron shielding and decrease in effective nuclear charge as becomes easier to loose valence shell electron.
2) Group 1 - more exothermic and float
Group 2 - Higher melting point and don’t float.
State the general equation for metals when:
1) Group 1 reacts with water
2) Group 2 reacts with water
1) 2 M + 2 H2O > 2 MOH + H2
2) M + H2O > M(OH)2 + H2
Explain why group 1 elements float on the water surface during a reaction.
Group 1 are less dense than water, group 2 have a higher density.
1) What is the general equation when metal reacts with water?
2) What is the general equation when metal reacts with acid?
1) Metal + Water > Salt + Hydrogen
2) Metal + Acid > Salt + Water
Metals are good reducing agents.
Mg + 2HCl > MgCl2 + H2
What would happen if dilute sulphuric acid was used?
Sulphate salt would be produced.
1) What solution is formed when oxides react with water (group 2)?
2) State an example.
3) State an example when elements react with oxygen.
1) Alkaline solutions
2) CaO + H2O > Ca(OH)2
3) 2 Mg + O2 > 2 MgO
1) What is the equation when magnesium oxide reacts with dilute acids?
2) What are the oxides acting as?
1) MgO + 2 H+ > Mg2+ +H2O
2) Acting as bases.
1) What is the general equation when group 1 metals react with oxygen?
2) What is the general equation when group 1 metals react with water?
1) 4 M + O2 > 2 M2O
2) 2 M + 2 H20 > 2 MOH + H2
What compound and precipitate is formed when Mg2+ reacts with:
1) Na2SO4
2) Na2CO3
3) NaOH
1) MgSO4 (aq) -no ppt
2) MgCO3 (s) - white ppt
3) Mg(OH)2 (s) - white ppt
What compound and precipitate is formed when Ca2+ reacts with:
1) Na2SO4
2) Na2CO3
3) NaOH
1) CaSO4 (aq) - slight ppt, sparingly soluble
2) CaCO3 (s) - white ppt
3) Ca(OH)2 (aq) - sparingly soluble, slight ppt
What compound and precipitate is formed when Ba2+ (test for sulphate ions) reacts with:
1) Na2SO4
2) Na2CO3
3) NaOH
1) BaSO4 (s) - white ppt
2) BaCO3 (s) - white ppt
3) Ba(OH)2 (aq) - no ppt
What does aq and s mean?
aq - soluble
s - insoluble
1) Are group 2 carbonates soluble or insoluble?
2) What is trend in group 2 sulphates as you go down the group?
3) What is trend in group 2 hydroxides as you go up the group?
1) Carbonates all insoluble.
2) Sulphates less soluble down the group.
3) Hydroxides less soluble up the group.
Explain how flame tests can be used in qualitative analysis.
All common elements in group 1 & 2 (except Mg) show characteristic flame colours that can be used to identify them.
State the flame colour of:
1) Lithium
2) Sodium
3) Potassium
4) Magnesium
5) Calcium
6) Strontium
7) Barium
8) Copper
1) Red
2) Yellow/Orange
3) Lilac
4) Colourless
5) Brick red
6) Crimson red
7) Apple green
8) Green
1) State an example when group 2 carbonates undergo thermal decomposition.
2) What happens to carbonates as you go down the group?
1) CuCO3 (s) [blue/green] > CuO (s) [black] + CO2 (g)
2) Carbonates become more stable to heat as you go down the group.
1) State the general equation for when group 2 hydroxides undergo thermal decomposition.
2) What happens to hydroxides as you go down the group.
1) X(OH)2 (s) > XO (s) + H2O (g)
2) Hydroxides become more stable to heat as you go down the group.
State at room temperature:
1) Chlorine and fluorine.
2) Bromine.
3) Iodine.
1) Gas
2) Liquid
3) Solid
What happens to the volatility of group 7 as you go down the group?
Less volatile, boiling points decrease due to higher Mr (size of atom increases), more electrons, stronger Van Der Waals forces between molecules.
Describe the reactivity of group 7 as you go down the group.
Less reactive as they need to gain an electron, greater electron shielding and decrease in effective nuclear charge.
State whether a reaction occurs:
1) Cl2 + KCl
2) Cl2 + KBr
3) Cl2 + KI
1) -
2) KCl + Br2
3) KCl + I2
State whether a reaction occurs:
1) Br2 + KCl
2) Br2 + KBr
3) Br2 + KI
1) x
2) -
3) KBr + I2
State whether a reaction occurs:
1) I2 + KCl
2) I2 + KBr
3) I2 + Ki
1) x
2) x
3) -
What is observed when group 7 elements react with metals?
Colourless crystalline salt, reactivity decreases down group 7 vice versa for group 1.
Describe how halide ions are identified. What is the importance of dilute nitric acid?
Silver nitrate test - dilute nitric acid added to solution, silver nitrate added. Dilute nitric acid prevents precipitation of any other salts.
How do you test the solubility of a precipitate?
Dilute and concentrated ammonia solution.
State observation when NaCl is added to:
1) AgNO3
2) NH3
1) White ppt
2) Dissolves in aqueous/clear solution
State observation when KBr is added to:
1) AgNO3
2) NH3
1) Cream ppt
2) Dissolves in concentrated ammonia - cloudy in dilute so doesn’t dissolve.
State observation when KI is added to:
1) AgNO3
2) NH3
1) Yellow ppt
2) Insoluble : doesn’t dissolve
State the advantages of chlorination and what it helps to prevent.
Kills microbes and bacteria, prevents outbreak fo diseases such as typhoid, cholera and dysntery.
What are the disadvantages of chlorination?
Highly toxic, react with organic compounds found in water supply (tirhalomethanes) to form chlorinated hydrocarbons which cab cause liver and kidney cancer.
State an advantage of fluoridation.
Reduces tooth decay by preventing cavities.
What are the disadvantages of fluoridation?
Cosmetic purposes, causes fluorosis (leads to tooth discolouration), forced mass medication as already in toothpaste and mouthwash.
State whether the following are soluble or insoluble:
1) Group 1 & ammonium compounds
2) Nitrates
3) Carbonates
4) Halides
5) Sulphates
1) Soluble
2) Soluble
3) Insoluble
4) Soluble except lead and silver halide
5) Soluble except lead and barium sulphate
How can we separate a soluble salt?
Crystallisation: heating & evaporating solution to half its original volume, leaving remaining solution to evaporate slowly. Crystallise and be filtered.
How can we separate an insoluble compound?
Appear as precipitation, separated by filtration.
Volatility
How readily a substance vaporises.
