The charges and sizes of the ions in an ionic compound affect the strength of the electrostatic attraction holding that compound together. Based on ion charges and relative ion sizes, rank these ionic compounds by their expected melting points from highest to lowest
a. SrCl2 ,b. CsBr ,c. RbCl ,d. SrS

Decreasing order of melting point:

SrS > > RbCl > CsBr

Explanation:

Born–Landé equation explained the relation between lattice energy, charges and sizes of ions present in a compound.

Here, U is internal energy, are charges and is the size.

More the lattice energy more will be the energy to break ionic lattice in order to melt.

Therefore, more the lattice energy, more will be melting point.

Moreover, lattice energy is proportional to charge and inversely proportional to size.

Consider the compounds given

In

In CsBr, charges are

In RbCl charges are

In Srs, charges on ions are

Order of the sizes are as follows:

Cs > Rb

Br > Cl

Cs > Sr

Therefore, decreasing order of melting point:

SrS > > RbCl > CsBr

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3