Question

Part A 

Determine whether the following pairs of elements can form ionic compounds. 

Part B 

What is the formula for an ionic compound that contains the elements magnesium and chlorine ?

Answer 1

ionic compounds: these compounds are formed from ions which are held together with the electrostatic force of attraction that means ions are of opposite charge(cation and anion). overall the molecule is neutral. The bonds between these ions are termed as ionic bonds. and the electronegativity difference between the atoms is very large.

covalent compounds: in these type of compounds atoms share their electrons to form covalent bonds here the overall molecule is neutral and unlike ionic compounds, the electronegativity difference between atoms is less.

ans:- Part A

ionic bond formation:- (lithium fluoride), (sodium fluoride), (calcium oxygen),(nickel chlorine)

in all these examples electronegativity difference is more than 1.7. In the case of nickel chlorine, electronegativity difference is not more than 1.7 but still, Ni-Cl bond has more than 50% ionic character in some of its compounds like [Ni(H2O)6]2+2Cl-

do not form ionic bond:- (nitrogen bromine), (sodium, magnesium)

nitrogen, bromine both are non-metals and sodium, magnesium both are metals so the electronegativity difference is very small so no ionic bond.

ans:- Part B

valency of Mg = 2 valency of Cl = 1

Mg is metal and will loos electron to form cation(Mg2+) and chlorine is non-metal thus it will gain electrons to form an anion(Cl-)

To form a neutral molecule two Cl- anions will be required to neutralise one Mg2+ cation. Thus, the formula will be MgCl2