Which of the following is a pure substance that contains two or more elements?

C) electrons encircling a nucleus with neutrons and protons

The correct answer is weight.

Firstly, the planetary model of the atom  failed  to explain why individual atoms produce discrete  line spectra. in fact, according to rutherford's model, each individual atom should produce a  continuous  line spectrum. the second flaw to his model was the fact that electrons orbit the nucleus in a circular fashion.