chemical properties of period 3 elements Flashcards
what is sand made out of?
silicon dioxide
what are the oxidation states for this reaction
2Na(s) + 2H2O (l) ~> 2NaOH(aq) + H2 (g)
oxidation state of sodium Na— 0
oxidation state of hydrogen H2O — 1
oxidation state of oxygen H2O — -2
oxidation state of sodium NaOH — 1
oxidation state of hydrogen NaOH — 1
oxidation state of oxygen NaOH — -2
oxidation state of hydrogen H2 — 0
redox reaction
what type of solution does sodium hydroxide produce?
alkaline aqueous solution
what type of pH does
1 mol Na2O + 1dm^3 H2O
13-14 pH
what type of solution does magnesium hydroxide form?
alkaline 9-10 pH
less soluble than sodium hydroxide
slower reaction
what does mg and H2O form?
Mg(s) + 2H2O (l) ~> Mg(OH)2 (aq) + H2 (g)
what does mg and steam form?
Mg (s) + H2O (g) ~> MgO (s) + H2 (g)
which of the period 3 elements react with cold or room temperature water?
sodium
magnesium
chlorine
which of the period 3 reactions with water undergo a redox reaction?
sodium and cold water
magnesium and cold water
magnesium and steam
what happens when oxygen reacts with sodium ?
burns with bright yellow flame
forming a white powder sodium oxide
Equation for oxidised sodium
4Na(s) + O2 (g) ~> 2Na2O(s)
what happens when magnesium reacts with oxygen?
Burns with a white flame
is oxidised
MgO is formed
what is the equation of the reaction between aluminium and oxygen?
4Al (s) + 3O2 (g) ~> 2Al2O3 (s)
what does aluminium form when reacted at high temperatures with oxygen?
aluminium oxide thin layer - aluminium foil
white powder
burns with white flame
what is the question when silicon reacts with oxygen?
Si(s) + O2 (g) ~> SiO2 (s)
what does phosphorus have if it’s atoms can be arranged differently?
2 allotropes
what are the two allotropes of phosphorus?
white phosphorus
red phosphorus
what happens when white phosphorus makes contact with oxygen at room temperature?
it spontaneously ignited
vigorous reaction
does red phosphorus react with oxygen at room temperature?
no
needs to be heated up before oxidation
produces white solid and white smoke like white phosphorus
what is the equation of phosphorus with oxygen?
4P(s) + 5O2 (g) ~> P4O10 (s)
what does sulfur form when heated and in contact with oxygen?
burns with blue flame
what is the highest formula of oxide?
SO3
what is the lowest formula of sulfur?
SO2
what is the most obvious physical trend in the period 3 elements is from metals on the left to non-metals on the right?
-sodium, magnesium, and aluminium
metallic
they are shiny (when freshly exposed to air)
conduct electricity and react with dilute acids to give hydrogen and salts
- silicon
semi- metal (metalloid)
conducts electricity to some extent
a property that is useful in making semiconductor devices
-phosphorus,sulfur and chlorine
non metals
do not conduct electricity
low melting and boiling points
-argon
noble gas
unreactive
exists as separate atoms
what type of reactions are the period 3 elements involved in?
oxidation?
redox?
reduction?
all redox reactions
since every element starts with an oxidation state of zero
after it has reacted it ends up with a positive or negative oxidation state
which elements are the only ones which react with cold water?
metals:
sodium
magnesium
all those reactions are redox ones, in which the oxidation state of the metal increases and that of some of the hydrogen atoms decreases
non metals:
chlorine
what does the reaction of sodium with water look like?
vigorous
sodium floats on the surface of the water and fizzes rapidly, melting because of the heat energy released by the reaction
what are the products of the reaction between sodium and water?
strongly alkaline solution of sodium hydroxide
(pH 13-14)
what’s is the equation and oxidation states for the reaction between sodium and water?
2Na (s) + 2H2O (l) ~> 2NaOH(aq) + H2(g)
0. +1. -2. +1. -2 +1. 0
what does the reaction between magnesium and water?
very slow at room temperature
only a few bubbles of hydrogen are formed after some days
what are the products of the reaction between magnesium and water?
solution is less alkaline than in the case of sodium because magnesium hydroxide is sparingly soluble
(pH around 10)
what is the equation and oxidation state of the reaction between magnesium and water?
Mg(s) + H2O(g) ~> MgO(s) + H2 (g)
0. +1.-2. +2. -2. 0
how can you make the reaction between water and magnesium quicker?
the reaction is much faster with heated magnesium and steam
what is the products of heated magnesium and steam?
magnesium oxide and hydrogen