What is the oxidation number of sulfur in sulfur dioxide?
+4
Among all elements in period 3, which one is the best conductor?
Aluminium
Mention two elements of period 3 which the oxides do not react with water!
Na, Mg
How does the trend of first ionisation energy across period 3?
Increases
How does the ionic radius of positively charged ions compared to its atom?
Ionic radius are much smaller
Mention three elements of period 3 which can react with water!
Na, Mg, Cl
Mention five elements of period 3!
Na, Mg, Al, Si, P, S, Cl, Ar
Why does chlorine have a very small melting point?
It has a simple molecule with strong covalent bond but weak van der Waals' forces
What happens when sodium reacts with oxygen?
Burns vigorously with yellow flame
Which chloride is neutral when reacts with water?
NaCl
What happens when the oxide of phosphor reacts with water?
Reacts vigorously and dissolves in water
How can we deduce the position of an element in the periodic table?
By looking at its physical and chemical properties
How does magnesium oxide and magnesium hydroxide work in our stomach?
They neutralise excess acid
Arrange these three elements from the most reactive one with chlorine: Si, Al, P
Al, Si, P
Why does atomic radius decrease across period 3?
Greater attractive force due to increasing positive nuclear charge, which pulls valence electrons closer to the nucleus.
Among elements in period 3, which one has the highest melting point?
Silicon
Between Mg2+ and S2-, which one has larger ionic radius?
S2-
Which gas will be released by phosphorus(V) oxide when it is hydrolysed in water?
HCl gas
Which oxide of period 3 element is amphoteric?
Aluminium oxide