Period 3 Flashcards
How are the blocks arranged in the periodic table?
S D P F
What is the characteristic of a transition meta/.
Form a compound in which they have a partially filled d-orbital.
Do metals get more or less reactive going down a group?
More
Do non-metals get more or less reactive going down the group?
Less
Why do the melting and boiling points of the metals from sodium to aluminium in period three increase?
From left to right the charge on the ion increases so there are more delocalised electrons and stronger metallic bonding.
Why does silicon have the highest boiling point?
Because of its giant structure.
Why does the atomic radius decrease across period three?
No new shells are formed, nuclear charge increases so electrons are pulled closer in.
What is first ionisation energy?
The amount of energy required to convert a mole of gaseous atoms to a mole of gaseous ions with a single + charge.
Why does the first ionisation energy increase across a period?
Nuclear charge increases but no new shells are started so it becomes increasingly difficult to remove one electron.
Why does first ionisation energy decrease going down a group?
Increased shielding and increased distance from nucleus so easier to remove.
Why does the atomic radius increase going down a group?
The atoms of each element have an extra shell of electrons compared to the one before.
Why is there a drop in ionisation energy from neon to sodium?
A new main energy level is started so there is an increase in atomic radius and shielding so the electron is easier to remove.
Why is there a drop in first ionisation energies between Magnesium and Aluminium.
Aluminium’s outer electron is in a 3p shell unlike magnesium which is in £s shell. 3p electron is easier to remove due to shielding.
Why is there a drop in first ionisation energy between phosphorus and sulfur?
Because sulfur has 2 electrons paired in its outer orbital, one of these is easier to remove than on on its own due to electron repulsion.
How does sodium react with water?
2Na + 2H2O –> 2NaOH + H2
What is the equation for magnesium reacting with water/steam?
Mg + 2H2O –> MgOH2 + H2
Why does magnesium reacting with water produce a less alkaline solution than sodium reacting with water?
Because magnesium hydroxide is barely soluble.
Which elements react directly with oxygen? What do the metals produce, what do the non-metals produce?
Sodium to sulfur.
Metals produce basic oxides.
Non-metals produce acidic oxides.
Give the equation for sodium reacting with oxygen. How would you carry out the experiment?
2Na +1/2O2 –> 2NaOH
Place hot sodium in a jar of oxygen.
Give the equation for magnesium reacting with oxygen. How would you carry out the experiment?
Mg + 1/2O2 –> MgO
Place burning magnesium ribbon in a gar of oxygen.
Give the equation for aluminium reacting with oxygen. How would you carry out the experiment?
4Al + 3O2 –> 2Al2O3
Sprinkle aluminium powder into a bunsen burner fame.
Give the equations for silicon, phosphorus and sulfur reacting with oxygen.
- Si + O2 –> SiO2
- 4P + 5O2 –> P4O10
- S + O2 –> SO2
What forms in the reaction between oxygen and phosphorus if the oxygen supply is limited?
Some P2O3 is formed.
How does the structure of period 3 oxides change going across from left to right?
Giant Ionic > macromolecular > Simple covalent.
Why does the bonding in aluminium oxide have covalent character?
High charge:size ratio can distort the electron cloud around the O^2- ion.
Which two oxides of period 3 are insoluble?
Aluminium oxide and silicon dioxide.
Give the equations for the oxides of period 3 reacting with water.
- Na2O + H2O –> 2NaOH
- MgO + H2O –> Mg(OH)2
- P4O10 + 6H2O –> 4H3PO4
- SO2 + H2O –> H2SO3
- SO3 + H2O –> H2SO4
Why is aluminium oxide insoluble in water?
Bonding in aluminium oxide is too strong for the lattice to dissociate.
What happens when the ionic period 3 oxides dissolve in water?
They first produce O^2- ions which are strong bases and react with water to form an alkaline solution.
Are the oxides of sodium and magnesium basic or acidic?
Basic
Are the oxides of silicon, phosphorus and sulfur acidic or basic?
Acidic
Which oxide of period three is amphoteric?
Aluminium.
Give equations for how sodium and magnesium oxides react with acids.
Na2O + 2HCl –> 2NaCl + H2O
MgO + H2SO4 –> MgSO4 + H2O
Give equations to show how aluminium reacts with an acid and a base.
Al2O3 + 6HCl –> 2AlCl3 + 3H2O
Al2O3 + 2NaOH + 3H2O –> 2NaAl(OH)4
Give equations to show how silicon dioxide react with a base?
- SiO2 + NaOH –> Na2SiO3 + H2O (sodium silicate)
How does phosphorus pentoxide react with a base?
- Phosphorus pentoxide reacts first with water to form phosphoric acid. Then: 3KOH + H3PO4 –> K3PO4 + H2O
How does Sulfur dioxide react with a base?
- SO2 + NaOH –> NaHSO3
NaHSO3 + NaOH –> Na2SO3 + H2O
