3.3 Chemical Properties Of Elements In The Same Group Flashcards
Why do elements in the same group in there periodic table react in the same way?
They have the same number of electrons in their outer shell.
How do the elements in group 1 (the alkali metals) react?
The atoms all have one electron in their outer shell and reactions virtually all involve the loss of this outer shell electron to form the positive ion M+.
How does the reactivity change down the group?
Reactivity increase because ionisation energy decreases as size of the atom increases - Cs loses its outer electrons to form a positive ion much more easily and will react more vigorously than Na.
How do alkali metal react with water?
2M(s) + 2H2O(l) —–> 2MOH(aq) + H2(aq)
How do alkali metals react with halogens?
2M(s) + X2(g) —–> 2MX(s)
What does the vigorous nature of the reaction depend on?
The particular halogen and alkali metal used, most vigorous reaction occurs between fluorine and caesium and the least vigorous between lithium and iodine.
How do the elements in group 17 react?
All have seven electrons in their outer shell and react either by gaining an electron to form the X- ion or by forming covalent compounds.
How does the reactivity change down group 17?
Reactivity decreases down the group.
How do displacement reactions of halogens work?
The more reactive halogen displaces the halide of the less reactive halogen from solution. Thus chlorine displaces bromide ions and iodide ions from solution and bromine displaces iodised ions from solution. Chlorine is a stronger oxidising agent than bromine, which is a stringer oxidising agent than iodine.
What is the reaction between Cl and KCl?
No reaction.
What is the reaction between Cl and KBr?
chlorine displaces bromide ions:
Cl2(aq) + 2Br-(aq) —–> 2Cl-(aq) + Br2(aq)
What is the reaction between Cl and KI?
Bromine displaces iodine ions:
Cl2(aq) + 2I-(aq) —–> 2Cl-(aq) + I2(aq)
What is the reaction between Br and KCl?
No reaction.
What is the reaction between Br and KBr?
No reaction.
What is the reaction between Br and KI?
Bromine displaces iodine ions:
Br2(aq) + 2I-(aq) —–> 2Br-(aq) + I2(aq)
