Question

he atomic radii of Li and O2- ions are 0.068 and 0.140 nm, respectively. (a) Calculate the force of attraction in newtons between these two ions at their equilibrium interionic separation (i.e., when the ions just touch one another). (b) What is the force of repulsion at this same separation distance

Answer 1

a

`F =  -1.07 *10^(-8) \  N`

b

`F_r = 1.07 *10^(-8) \ N`

Step-by-step explanation:

Generally the force of attraction between this two irons is mathematically represented as

`F = (k * [Q_(Li) ] * [Q_(O) ] )/( r^2)`

Here k is known as the proportionality constant with value
`k = 2.31 * 10^ {-28} J \cdot m`

substituting -2 for
`Q_(O)` i.e the charge on oxygen , +1 for
`Q_(Li)` i.e the charge on Lithium and
`[0.140 + 0.068 ] nm= 0.208 nm = 0.208*10^(-9)` for r

So

`F = \frac{ 2.31 * 10^ {-28}* +1 * -2 }{ ( 0.208*10^(-9) )^2 }`

`F = -1.07 *10^(-8) \ N`

Generally the force of repulsion will be the magnitude but different direction to the force o attraction

So Force of repulsionn is

`F_r = 1.07 *10^(-8) \ N`