The most appropriate answer is B !!
Covalent bond is formed by sharing of electrons !!
Metallic bonds<span>, the valence electrons from the s and p orbitals of the interacting metal atoms delocalize</span>
After the dillution of the solution, the wavelength of maximum absorption is decreased.
<h3>What is the wavelength of maximum absorption?</h3>
The wavelength of maximum absorption is the wavelength at which the solution absorbs the maximum amount of light. It is usually shown as a hump in the spectrum.
When the starting concentration of the K2Cr2O7 is diluted, the wavelength of maxium absorption decreases.
Learn more about maximum absorption: brainly.com/question/26610701
As we know that there are avogadro no. of atoms in 9 g of beryllium.
1 mole of beryllium = 6.02 * 10^23 atoms
so 2.5 mole= 6.02*10^23*2.5 i.e = <span>15.055 × 10^23 atoms </span>