The period 3 elements
Write and equation to show the reaction of Aluminum with oxygen
2Al + 1½O₂→Al₂O₃
Write an equation to show the reaction of sodium with water
2Na + 2H₂O→ 2NaOH + H₂
Write equations for reactions of sodium with oxygen
2Na + ½O₂ →Na₂O
Write an equation for the reaction between phosphoric(V) acid and magnesium oxide
3MgO + 2H₃PO₃ → Mg₃(PO4)₂ + 3H₂O
Write an equation for the acid-base reaction that occurs when Na₂O reacts with P₄O₁₀ in the absence of water.
6Na₂O + P₄O₁₀ → 4Na₃PO₄
Explain why the oxides of the Period 3 elements sodium and phosphorus have different melting points. In your answer you should discuss the structure of and bonding in these oxides, and the link between electronegativity and the type of bonding.
A big difference in electronegativity leads to ionic bonding whilst a small difference in electronegativity leads to covalent bonding. Sodium oxide is an ionic lattice with strong forces of attraction between ions. Phosphorus oxide has a covalent molecular structure.It has weak intermolecular forces between molecules that can easily be broken. This is why the melting point of sodium oxide is higher than the melting point of phosphorus oxide.
Write equations for two reactions which together show the amphoteric character of aluminium hydroxide.
Al(OH)₃ + OH⁻ → Al(OH)₄⁻ Al(OH)₃ + 3H⁺ + 3H₂O → Al(H₂O)₆³⁺
Describe the structure and bonding of alminium oxide and link this to how it can react with water
Although the bonding in aluminium is ionic, it is too strong for the ions to be separated. This is partly due the the additional covalent bonding it has
Write an equation to show how aluminium oxide reacts with concentrated sodium hydroxide to produce sodium aluminate
Al₂O₃ + 2NaOH + 3H₂O → 2NaAl(OH)₄
Write an equation to show how aluminium oxide reacts with hydrochloric acid to produce Aluminium chloride
Al₂O₃ + 6HCl→ 2AlCl₃ + 3H₂O
A waste-water tank was contaminated by P4O10. The resulting phosphoric(V) acid solution was neutralised using an excess of magnesium oxide. The mixture produced was then disposed of in a lake.Explain why the use of an excess of sodium hydroxide to neutralise the phosphoric(V) acid solution might lead to environmental problems in the lake.
An excess of NaOH would make the lake alkaline ( increase the pH) and this would kill wildlife
State the element in Period 3 that has the highest first ionisation energy. Explain your answer
Argon has the higest furst ionisation energy because it has the largest nuclear charge but the same amount of shielding as the number of shells are the same across the period.
When comparing the atomic sizes of the period 3 elements argon is left out. Explain why
Atomic radii are taken to be half the distance between the centres of a pair of atoms. Argon, however, does not bond covalently with one another. Because they do not have covalent radii they are left out of comparisons of atomic sizes.
Describe and explain the trends across Period 3 in atomic radius.
Atomic radius decrease across the period because the nuclear charge increases but electrons are in the same shell. As you go across the period the attraction between the nucleus and the outer electron increases
Describe the reaction of sulfur with oxygen
Blue flame, colourless sulfur dioxide gas and misty fumes of smelly gas are produced.
Describe the reaction of Aluminum with oxygen
Bright white flame and white powder produced
Describe the reaction of Magnesium with oxygen
Bright white flame and white powder produced
Describe the reactions of sodium with oxygen
Bright yellow flame and white powder produced
Sulfur dioxide reacts with the base calcium oxide to form calcium sulfite. This is the first step of one of the methods of removing sulfur dioxide from the flue gases in power stations. Write an equation to show the reaction between sulfur dioxide and calcium oxide
CaO + SO₂→CaSO₃
In the production of iron, at high temperatures inside the blast furnace, calcium oxide reacts with the impurity silicon dioxide to produce calcium silicate. Write an equation to show how silicon dioxide act as an acidic oxide when reacting with the base.
CaO + SiO₂ → CaSiO₃
Suggest why the melting point of magnesium oxide is much higher than the melting point of magnesium chloride.
Charge on oxide ion bigger than on chloride therefore electrostatic attraction is stronger
Suggest the element in Period 3 that has the highest electronegativity value
Chlorine
Identify the block in the Periodic Table to which copper belongs
D block
State and explain the trend in electronegativities across Period 3 from sodium to sulfur.
Electronegativity increases.Proton number increases so nuclear charge increases. There are the same number of electron shells so the attraction of bond pair to nucleus increases .
Explain why chromium is placed in the d block in the Periodic Table.
Highest energy electron is in the 3d orbital
Explain why in some periodic tables hydrogen is place group 7.
Hydrogen can form -1 ions in some reactions and it can also bond covalently
Magnesium burns with a bright white light and is used in flares and fireworks.Explain why water should not be used to put out a fire in which magnesium metal is burning.
Hydrogen is produced so risk of explosion
Describe and explain the trends across Period 3 in ionisation energy
IE increase because the nuclear charge increases across the period and the electron is taken from the same shell.
Explain how the type of bonding in P4O10 can be predicted by a consideration of electronegativity.
In covalent bonding the electronegativity difference small. Big difference in electronegativity leads to ionic bonding.
Some Period 3 oxides have basic properties. State the type of bonding in these basic oxides. Explain why this type of bonding causes these oxides to have basic properties.
Ionic bonding causes oxides to have basic properties because the oxides contain oxide ions which accept protons to form water.
Hydrogen is a gas whilst group 1 elements are reactive metals. Despite this difference in some periodic tables hydrogen is placed above the group 1 elements. Explain why.
It forms +1 ions like the rest of the elements in group 1
Suggest why silicon dioxide is described as an acidic oxide even though it is insoluble in water
It reacts with bases
Why is helium placed above the noble gases in some periodic tables?
It shares the same properties as the noble gases
Why is helium not a p-block element
Its electron configuration is 1S²
Is helium an s or p block element?
Its put in the P block because it has the same properties as noble gases however it can also be put in the s block because it's out electron are in the s orbital
Sodium, aluminium and silicon are solid elements with a silver colour. These elements react with oxygen to form oxides with high melting points. Aluminium is a reactive metal, but it resists corrosion in water because it has a surface coating of aluminium oxide. In terms of its structure and bonding, explain why silicon dioxide has a high melting point
Macromolecular .Covalent bonding between atoms. strong bonds to be broken.
Both magnesium and sodium oxide contai the oxide ion O²⁻ which is a very strong base that strongly attracts protons.Explain then why sodium oxide forms a solution with a higher pH when it reacts with water than magnesium oxide
Magnesium oxide is less soluble than sodium oxide.
Describe and explain the trends across Period 3 in melting points.
Melting and boiling points increases across the three metals because of the increasing strength of the metallic bonds. The number of delocalised electrons which surrounds each atom increases. The atoms also get smaller and have more protons.
State the method used to reduce aluminium oxide on an industrial scale. Give the essential conditions for this industrial process.
Method: Electrolysis Conditions: Molten, high T, Cryolite
Write an equation to show the reaction of Magnesium with water at room temperature
Mg + 2H₂O→Mg(OH)₂ + H₂ Mg + H₂O→ MgO + H₂
Write an equation to show the reaction of heated Magnesium with steam.
Mg + H₂O→ MgO + H₂
Write an equation to show the reaction of Magnesium with oxygen
Mg + ½O₂→MgO
Explain why the melting point of magnesium chloride is much higher than the melting point of silicon tetrachloride
MgCl2 is ionic whereas SiCl4 is simple covalent. There are Van der Waals forces between silicon tetrachloride. Ionic forces present in magnesium chloride is stronger than VdW, therefore more energy required to separate the particles in MgCl2
Write an equation to show why magnesium oxide is classified as a basic oxide
MgO + 2HCl → MgCl₂ + H₂O
Write an equation for the reaction of magneisum oxide with water and suggest the pH value of the resulting solution
MgO + H₂O→ Mg(OH)₂ ⇌ Mg²⁺ + 2OH⁻ pH 9
A waste-water tank was contaminated by P4O10. The resulting phosphoric(V) acid solution was neutralised using an excess of magnesium oxide. The mixture produced was then disposed of in a lake. Explain why an excess of magnesium oxide can be used for this neutralisation.
MgO is insoluble ( and weakly alkaline). unreacted MgO can be filtered off.
Write an equation for the reaction of sodium oxide with water and suggest the pH value of the resulting solution
Na₂O + H₂O→ 2Na⁺ + 2OH⁻ pH 14
Write an equation to show why sodium oxide is classified as a basic oxide
Na₂O + H₂SO₄→ Na₂SO₄ + H₂O
Write an equation for the reaction of aluminium oxide with water and suggest the pH value of the resulting solution
No reaction as aluminium oxide is insoluble in water
Write an equation for the reaction of silicon dioxide with water and suggest the pH value of the resulting solution
No reaction as silicon dioxide is insoluble in water
Phosphorus(V) oxide is known as phosphorus pentoxide. Suggest why it is usually represented by P4O10 rather than by P2O5
One molecule contains 4P and 10O
Describe and explain the trend in melting points of period 3 oxides
Overall the melting point decrease as you go across the period. The exception is between magnesium and sodium as magnesium oxide has a higher melting point than sodium oxide
Suggest one reason why a thin layer of aluminium oxide protects aluminium from corrosion in moist air.
Oxide is Insoluble in water and inert
Suggest one property of the aluminium oxide coating that causes aluminium to resist corrosion in water.
Oxide is inert ,Insoluble, impermeable, non porous
The reaction between phosphorus pentachloride and water.
PCl₅+ 4H₂O → H₃PO₄ + 5HCl
Write an equation to show the reaction of phosphorus with oxygen
P₄ + 5O₂→P₄O₁₀
Equations to show why phosphorus pentoxide is classified as an acidic oxide
P₄O₁₀ + 12NaOH → 4Na₃PO₃ + 6H₂O
Write equations to show why phosphorus pentoxide is classified as an acidic oxide
P₄O₁₀ + 12NaOH → 4Na₃PO₃ + 6H₂O
Write an ionic equation for the reaction of phosphorus(V) oxide with an excess of sodium hydroxide solution.
P₄O₁₀ + 12OH⁻ → 4PO₃⁻ + 6H₂O
Write an equation for the reaction of phosphorus pentaoxide with water and suggest the pH value of the resulting solution
P₄O₁₀ + 6H₂O → 4H₃PO₄ pH 2
Write an equation to show the reaction of sulfur with oxygen
S + O₂ → SO₂
Elements in the periodic table are classified into block elements. Name the block elements
S,P,D,F
Write an equation for the reaction of sulfur(IV) oxide with water and suggest the pH value of the resulting colourless solution.
SO₂ + H₂O → H₂SO₃ pH2
Suggest, in terms of structure and bonding, why the melting point of sulfur(IV) oxide is different from that of phosphorus(V) oxide
SO₂ is a smaller molecule than P₄O₁₀. The van der Waals' forces between molecules are weaker and so require less energy to separate them.
Write an equation for the reaction of sulfur trioxide with water and suggest the pH value of the resulting solution
SO₃ + H₂O → H₂SO₄ pH 1
What do the letters s,p,d,f stand for?
Sharp, principle,diffuse,fine
Write an equation to show the reaction of silicon with oxygen
Si + O₂→SiO₂
By considering the structures and the bonding involved explain why .SiCl4 is a liquid at room temperature but PCl5 is a solid with a higher melting point.
SiCl4 has a simple molecular structure with weak van der Waals forces between molecules. PCl5 has an ionic structure. Ionic forces stronger than van der Waals'.
Write an equation for the reaction that occurs when silicon tetrachloride is added to water. Predict the pH of the resulting solution.
SiCl₄ + 4H₂O → Si(OH)₄ + 4HCl (or SiCl₄ + 2H₂O → SiO₂ + 4HCl) pH 1
Write an equation to show why silicon dioxide is classified as an acidic oxide
SiO₂ + 2NaOH → Na₂SiO₃ + H₂O Silicon dioxide reacts with a base
State metal oxide in Period 3 that has the highest melting point. Explain your answer
Silicon dioxide has the highest melting point because it has covalent bonds throughout its giant structure. These covalent bonds are strong and a lot of energy is required to break them.
Describe the structure and bonding of silicon dioxide and link this to how it can react with water
Silicon dioxide is a giant macromolecule and so water will not affect this type of struture
Describe the reaction of silicon with oxygen
Silicon dioxide is produced
Suggest why silicon dioxide is described as an acidic oxide even though it is insoluble in water.
Silicon dioxide reacts with bases such as NaOH and CaO.
State the element in period 3 that has the highest melting point and expain your answer.
Silicon has the highest melting point because it has covalent bonds throughout its giant structure. These covalent bonds are strong and a lot of energy is required to break them.
Explain why the reaction of the period 3 elements are all redox reactions.
Since every element starts with an oxidation state of zero , and after it has reacted ends up with a positive or negative oxidation state.
State the element in Period 3 that has the highest second ionisation energy. Explain your answer
Sodium
Predict the element in Period 3 that has the highest second ionisation energy. Give a reason for your answer.
Sodium because the electron is removed from the 2p orbital.
Explain, in terms of structure and bonding, why sodium oxide has a high melting point.
Sodium oxide has a giant ionic structure. The strong attraction between the oppositely charged ions require a lot of energy to overcome.
Explain, in terms of structure and bonding, why sodium oxide has a high melting point
Sodium oxide is an ionic lattice. There is a strong attraction between oppositely charged ions so lots of energy required to overcome attraction.
Other than sodium oxide, what other products can be produced when sodium reacts with oxygen
Sodium peroxide
Sulfur dioxide an sulfur trioxide both react violently with water to produce an acid which partially dissociates to produce hydrogen ions. Name the acid that each oxide produces
Sulfur dioxide reacts with water to produce sulfurous acid. Sulfur trioxide reacts with water to produce sulfuric acid.
What is different about sulfur when it reacts with oxygen compared to the other period 3 elements?
Sulfur is the only period 3 element that does not form an oxide when it reacts with oxygen. It forms dioxide instead.
Describe the structure and bonding of sulfur oxides and link this to how it can react with water
Sulfur oxides are all covalent molecules that react with water to form acid solutions
Explain, in terms of structure and bonding, why sulfur trioxide has a higher melting point than sulfur dioxide
Sulfur trioxide is a larger molecule than sulfur dioxide so the van der Waals' forces between the molecules are stronger.
When sodium reacts with water it starts to melt. Explain why
The melting is caused by the heat energy released by the reaction.
What is the periodic table meant for?
The periodic table is not just meant to indicate electronic configuration, but also groups with similar properties.
White phosphorus is a hazardous form of the element. It is stored under water. Suggest why white phosphorus is stored under water.
To prevent it reacting with oxygen
Describe the reaction of Magnesium with water at room temperature
Very slow reaction. Only a few bubbles of hydrogen gas form
Describe the reactions of sodium with water
Vigorous reaction. Sodium floats on the water and fizzes.
What are the letters s,p,d,f used to descirbe
When elements are heated they give out light energy at certain wavelengths , as excited electrons are fall back from one energy at certain wavelengths , as excited electrons fall back from one energy level to a lower one. This causes lines to appear in the spectrum of light they give out . The s,p,d,f letters stand for the words used to describe the lines formed.
Describe the reaction of phosphorus with oxygen
White smoke
Describe the reaction of heated Magnesium with water at room temperature
White solid and a bright white flame
State why iron is placed in the d block of the Periodic Table
outermost electrons in the d orbital;
Explain why phosphorus(V) oxide has a higher melting point than sulfur(VI) oxide.
phosphorus(V) oxide is a bigger molecule than sulfur(VI) oxide. The Van der Waals forces between molecules are stronger and therefore require more energy to break.
