Question

which answer completes the chart? 26 fe iron 6.941 chemical symbol element name atomic mass atomic number formula code electron level reactivity factor

Explanation:

In the periodic - table, each element has a unique atomic number. For iron (Fe), the number 26 represents its atomic number, which is the number of protons in the nucleus of an atom of that element. There is no such thing as a "formula code" in this context. Electron levels describe the distribution of electrons around the nucleus and are not simply a single number like 26 for an element. Reactivity factor is not represented by a single number like 26 for an element in the basic element - identification context.

Answer:

atomic number