Which of the following pairs are isotpes? A) H-3 & He-4
B) Mg with 12 protons & Na with 12 neutons
C) Al-27 & Co with 27 protons
D) O-16 & O-18

The answer is B because isotopes have the same number of protons and neutrons.

Answerrestate the main idea,essay or thesis, summarize the three subpoints of your essay, leave the reader with an interesting final impression;

Electron equations of the given changes are as follow,a)                              cu      →      cu⁺²  + 2e⁻b)                              mg⁺²  +  2 e⁻      →      mgc)                              cl⁻    →      cl  +  1e⁻d)                              s  +  2 e⁻    →      s²⁻e)                                o²⁻      →      o  +  2 e⁻f)                              p  +  3 e⁻    →      p³⁻g)                              fe²⁺    →      fe³⁺  + 1 e⁻h)                              s²⁻    →      s⁴⁺  +  6 e⁻