2.4 Properties Of Period 3 Elements And Their Oxides Flashcards
Appearance and physical properties of sodium
Metallic, shiny, conducts electricity (worst conductor out of the metals)
Reaction of sodium with acid?
Na + acid —> H2 + salt
Reaction of sodium with cold water - equation and observations
Vigorous reaction, floats on water,fizzes melts due to -△H of the reaction. NaOH is pH 13-14.
2Na + 2H2O —> 2NaOH + H2
Reaction of sodium with oxygen (equation and observation)?
Bright yellow flame, forms white powder of Na2O
2Na + 1/2 O2 —> Na2O
Appearance and physical properties of magnesium
Metallic, shiny, conducts electricity (between Na and Al in terms of how well it does)
Reaction of Mg with cold water (observation and equation)
Very slow reaction. pH = 10 as Mg(OH)2 is sparingly soluble
Mg + 2H2O —> H2 + Mg(OH)2
Reaction of Mg with steam (observation and equation)? I’m
Much faster
Mg + H2O —> MgO + H2
Reaction of Mg with oxygen (observation and equation)?
Bright white flame, forms white powder of MgO
2!g + O2 —> 2MgO
Appearance and physical properties of aluminium?
Metallic, shiny best conductor of electricity in period 3
Reaction of Al with cold water?
No readtion
Reaction of Al with oxygen (observation and equation)?
Heat and lower into jar of O2–> bright flame, forms white powder
4Al + 3O2 —> 2Al2O3
Why is aluminium considered unreactive even through the metal itself is reactive
Covered by Al2O3 from where oxygen has oxidised the surface of the Al. Al2O3 is unreactive. Makes it useful for saucepans, window frames etc.
If Al2O3 is scratched off, Al reacts rapidly with air to form a new coat
Appearance and physical properties of silicon
Semimetal (metalloid), semiconductor (conducts electricity to an extent and in certain conditions)
Reaction of silicon with oxygen (observations and equations)?
Heat strongly
Si + O2 —> SiO2 (white powder)
Appearance and physical properties of phosphorus
Non-metal, low m.p. And b.p. Does not conduct electricity
Red phosphorus as a crystal structure
White phosphorus as P4
Reaction of phosphorus in excess oxygen (observations and equations)?
Red P needs to be heated significantly first, white P ignites spontaneously in air
Phosphorus pentoxide (white crystalline solid) formed
4P + 5O2 —> P4O10
Reaction of phosphorus in limited oxygen (observations and equation)?
Incomplete combustion: colourless liquid phosphorus trioxide s formed
4P + 3O2 —> P4O6
Appearance and physical properties of sulfur?
Non-metal, low mp and bp, does not conduct electricity
Reaction of sulfur with oxygen (observations and equation)?
Need to heat and lower into a jar of oxygen. Colourless gas sulfur dioxide formed. Some SO3 also formed.
S+O2–> SO2
What are the different types of structure and bonding displayed by the period 3 oxides?
Na ionic lattice
Mg ionic lattice
Al ionic lattice with covalent character; Al3+ distorts O2- electron cloud
Si giant covalent
P simple molecular covalent
S simple molecular covalent