PERIOD 3

What is the trend in atomic radius across group 3?

• decreases

• the nuclear charge increases as there are more protons while the shielding stays the same. this means there is a greater force of attraction between the nucleus and the outer electron shell

What is the general trend in the first ionisation energy across period 3?

general increase as the nuclear charge increases while the shielding stays the same meaning there is a greater force of attraction to remove an outer electron

Why is there a dip in the first ionisation energy between group 2 and 3?

in Al the outer electron is in a 3p orbital while in Mg the outer electron is in the 3s orbital. the 3p orbital is higher in energy meaning it requires less energy to overcome to remove an electron

Why is there a dip in the first ionisation energy between group 5 and 6?

in P the p orbital is 3p3 while in S it is 3p4. there is electron pair repulsion in the 3p4 orbital as electrons share the same subshell meaning it requires less energy to remove an electron

What is the trend in electronegativity across period 3?

increases as the nuclear charge increases while the shielding stays the same. this means that there is a greater force of attraction between 2 electrons in a covalent bond

What is the trend in the melting and boiling points going across group 3 from sodium to aluminium?

increases. this is because the nuclear charge increases and the number of delocalised electrons increases. this means that there is a greater force of attraction which requires more energy to overcome

What is the trend in the melting and boiling points going across group 3 with silicon?

increases. this is because it forms a giant macromolecular lattice which has strong covalent bonds which requires more energy to overcome

What is the trend in the melting and boiling points going across group 3 from phosphorus to chlorine?

decreases as they are simple molecules with weak Van der Waals. phosphorus has the highest melting and boiling point as it has the greatest number of electrons

What is the trend in the melting and boiling point of argon?

very low as it is monatomic meaning there are weak van der waals between the molecules

What is the melting point of sodium?

98

What is the structure and bonding in sodium?

metallic

What’re observations when sodium reacts with water?

• floats and moves on water

• fizzes and may catch fire

• burns with a yellow-orange flame

What is the equation of sodium reacting with water?

2Na + 2H2O —> 2NaOH + H2

What’re observations when sodium reacts with oxygen?

• burns with a yellow-orange flame

• produces a white powder

What is the equation to sodium reacting with oxygen?

4Na + O2 —> 2Na2O

What is the melting point of magnesium?

650

What is the structure and bonding of magnesium?

metallic

What are observations of the reaction of magnesium with steam?

• burns with a white flame

• forms a white powder

What’re observations for the reaction of magnesium with water?

very slow reaction

What is the equation for the reaction of magnesium with steam?

Mg + H2O —> MgO + H2

What is the equation for the reaction of magnesium with water?

Mg + 2H2O —> Mg(OH)2 + H2

What’re the observations with magnesium reacting with oxygen?

• burns with white flame

• produces a white powder

What is the equation of the reaction between magnesium and oxygen?

2Mg + O2 —> 2MgO

What is the melting point of aluminium?

660

What is the structure of aluminium?

metallic

What are observations of the reaction of aluminium with oxygen?

• burns with a white flame

• produces a white powder

What is the equation of the reaction between aluminium and oxygen?

4Al + 3O2 —> 2Al2O3

What is the melting point of silicon?

1414

What is the structure and bonding of silicon?

giant covalent

What are the observations of the reaction between silicon and oxygen?

• burns with a white flame

• produces a white powder

What is the equation for the reaction between silicon and oxygen?

Si + O2 —> SiO2

What is the melting point of phosphorus?

44

What is the structure and bonding in phosphorus?

molecular

What are the observations of the reaction of phosphorus with oxygen?

• burns with a very bright white flame

• produces a white powder

What is the equation for the reaction between phosphorus and oxygen?

P4 + 5O2 —> P4O10

What is the melting point of sulfur?

95

What is the structure and bonding in sulfur?

molecular

What’re observations to the reaction between sulfur and oxygen?

• burns with blue flame

• gives off a choking gas

What is the equation for the reaction of sulfur and oxygen?

S + O2 —> SO2

What is the melting point of chlorine?

-102

What is the structure and bonding in chlorine?

molecular

What is the observations of the reaction of chlorine with water?

dissolves giving a pale green solution

What is the equation for the reaction between chlorine and water?

Cl2 + H2O —> HCl + HOCl

What is the melting point of sodium oxide?

1275

What is the structure of sodium oxide?

ionic

What occurs if sodium oxide is reacted with water?

dissolves then reacts with water to form a solution

What is the equation for the reaction of sodium oxide with water?

• Na2O + H2O —> 2NaOH

• Na+ and O2- ions dissolve in water and O2- ions react with water

• O2- + H2O —> 2OH-

What is the pH of the solution when sodium oxide reacts with water?

14

What is the equation for the reaction of sodium oxide with acids?

Na2O + 2H+ —> 2Na+ + H2O

What is the nature of sodium oxide?

basic

What is the melting point of magnesium oxide?

2900

What is the structure of magnesium oxide?

• ionic

• has a higher melting point than sodium oxide as Mg2+ ions are smaller and higher charged

What happens when magnesium oxide reacts with water?

• slightly soluble

• some dissolves and reacts with water to form a solution

What is the equation for the reaction between magnesium oxide and water?

• MgO + H2O —> Mg(OH)2

• some Mg2+ and O2- ions dissolve in water and the O2- ions react with water

• O2- + H2O —> 2OH-

What is the pH of the solution formed when magnesium oxide reacts with water?

10

What is the equation for the reaction of magnesium oxide with acids?

MgO + 2H+ —> Mg2+ + H2O

What is the nature of magnesium oxide?

basic

What is the melting point of aluminium oxide?

2040

What is the structure and bonding of aluminium oxide?

• ionic

• not as high a melting point due to covalent character due to polarising nature of Al3+ ions

What happens in the reaction of aluminium oxide with water?

nothing as it is insoluble

Why is aluminium oxide insoluble?

due to a very high lattice enthalpy

What is the equation for the reaction between aluminium oxide and acids?

Al2O3 + 6H+ —> 2Al3+ + 3H2O

What is the equation for the reaction between aluminium oxide and alkalis?

Al2O3 + 2OH- + 3H2O —> 2Al(OH)4

What is the nature of aluminium oxide?

amphoteric

What is the melting point of silicon dioxide?

1610

What is the structure of silicon dioxide?

giant covalent

What happens in the reaction between silicon dioxide and water?

nothing as it is insoluble

Why is silicon dioxide insoluble?

lattice of atoms are linked by strong covalent bonds that would have to be broken

What is the equation for the reaction of silicon dioxide with alkalis?

SiO2 + 2OH- —> SiO32- + H2O

What must the alkali be if it is reacting with silicon dioxide?

hot concentrated NaOH

What is the nature of silicon dioxide?

acidic

What is the melting point of P4O10?

580

What is the structure of P4O10?

simple molecular

What occurs in the reaction between water and P4O10?

reacts violently

What is the equation of the reaction between P4O10 and water?

• P4O10 + 6H2O —> 4H3PO4

• H2O attach to the P atoms, leading to the release of H+ ions from the water molecules

What is the pH of the solution formed when P4O10 reacts with water?

0

What is the equation of the reaction between P4O10 and alkalis?

P4O10 + 12OH- —> 4PO43- + 6H2O

What is the nature of P4O10?

acidic

What is the melting point of sulfur dioxide?

-75

What is the structure of sulfur dioxide?

• simple molecular

• bent shape

• bond angles of 119

What occurs in the reaction between sulfur dioxide and water?

dissolves and reacts with water to form a solution

What is the equation for the reaction of sulfur dioxide with water?

• SO2 + H2O —> H2SO3

• H2O molecules attach to the S atoms leading to the release of H+ ions from water molecules

What is the pH of the solution formed when sulfur dioxide reacts with water?

3

What is the equation for the reaction between sulfur dioxide and alkali?

SO2 + 2OH- —> SO32- + H2O

What is the nature of sulfur dioxide?

acidic

What is the melting point of sulfur trioxide?

17

What is the structure of sulfur trioxide?

• simple molecular

• trigonal planar

• bond angles of 120

What occurs in the reaction between sulfur trioxide and water?

reacts violently

What is the equation for the reaction between sulfur trioxide and water?

• SO3 + H2O —> H2SO4

• H2O molecules attach to the S atoms leading to the release of H+ ions from water molecuels

What is the pH of the solution formed in the reaction between sulfur trioxide and water?

0

What is the equation for the reaction between sulfur trioxide and alkalis?

SO3 + 2OH- —> SO42- + H2O

What is the nature of sulfur trioxide?

acidic