Question

A divalent monoatomic cation (atomic number Z) is
isoelectronic of CO2 and has (Z + 2) neutron. What is
ionic mass of divalent cation.
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Answer 1

Answer:

As the it is a divalent cation ,let it be X2+.

Number of electrons in CO2 is 6+8+8=22 electrons.

As X2+ is isoelectronic with CO2 .So number of electrons in it is 22.

Number of electrons in its neutral atom is 22+2=24(Because X had lost electron to become X2+).Hence the atomic number of X is 24.

number of protons(Z)=atomic number =24

number of neutrons=Z+2=26

Mass Number=Z+Z+2=50u

Formula of its carbonate= XCO3

Molecurar mass of its carbonate=50+12+16 x 3=110

Hence 1mole=110 g=6.023x1023

=> 55g=6.023 x 1023/2 =3.011x1023

Hence the number of molecule is 3.011x1023