Calculate the amount of energy required for the formation of one mole of MgSe bonds (not lattice energy). The radius of the magnesium ion is 0.65 A, and the radius of the selenide ion is 1.98 A. Note that 1 A=10^-10m.
To calculate the amount of energy required for the formation of one mole of MgSe bonds, we need to use the concept of lattice energy. Lattice energy is the energy released when ions come together to form a solid ionic compound.
However, the question specifies that we should not calculate lattice energy. Instead, we need to consider the energy required for the formation of MgSe bonds.
The formation of bonds involves the transfer of electrons and the resulting electrostatic attraction between the ions. In this case, magnesium (Mg) loses two electrons to form a 2+ cation, and selenium (Se) gains two electrons to form a 2- anion.
To calculate the energy required for the formation of MgSe bonds, we need the following steps:
Step 1: Calculate the electrostatic potential energy between the two ions using Coulomb's law:
The formula for Coulomb's law is:
E = k * (q1 * q2) / r
where E is the electrostatic potential energy, k is the electrostatic constant (8.99 x 10^9 N m^2/C^2), q1 and q2 are the charges of the ions, and r is the distance between the ions.
In this case, Mg is a 2+ cation, and Se is a 2- anion. So the charges of the ions are q1 = +2 and q2 = -2.
The distance between the ions (r) can be calculated by adding the radius of Mg (0.65 Å) and the radius of Se (1.98 Å). However, both radii need to be converted to meters:
0.65 Å = 0.65 x 10^-10 m
1.98 Å = 1.98 x 10^-10 m
Therefore, r = 0.65 x 10^-10 m + 1.98 x 10^-10 m.
Step 2: Calculate the energy for one mole of MgSe bonds.
Since we have one mole of MgSe bonds, we need to multiply the energy calculated in step 1 by Avogadro's number (6.022 x 10^23 mol^-1) to get the energy per mole.
So, the energy required for the formation of one mole of MgSe bonds can be calculated using the above steps.