which of the following diagrams best depicts an alloy of ni and b?

Explanation:

Step1: Recall alloy definition

An alloy is a mixture of metals or a metal and a non - metal. In a solid - state alloy of Ni (nickel, a metal) and B (boron, a non - metal), the atoms of B are often in the interstitial sites of the Ni lattice.

Step2: Analyze diagrams

In option A, the smaller grey circles (representing B atoms) are in the interstitial spaces between the larger white circles (representing Ni atoms), which is characteristic of an interstitial alloy. Option B shows pairs of atoms bonded together, which is not typical for an alloy structure. Option C shows a more random distribution of two types of atoms without the characteristic interstitial arrangement.

Answer:

A.