Only 2 questions me

1. which reaction substitutes one element in a reactant with another to form a product?

single-displacement

combustion

synthesis

double-displacement

2.which choice correctly describes the subatomic particles in the isotope 28mg?

28 protons, 12 electrons, 28 neutrons

12 protons, 12 electrons, 16 neutrons

12 protons, 12 electrons, 12 neutrons

12 protons, 16 electrons, 28 neutrons

Can anyone explain 1. review your spectrometry data and use the known elements to identify the star's composition. which unknown elements make up this star? justify your element selections. 2. in parts i and ii of the lab, what happened to the electrons of each element to produce the different colors of light? explain your answers using important terms from the lesson and information provided in the laboratory. 3. stars composed of heavier (more massive) elements are often slightly older than stars made predominantly from hydrogen and helium. based on your data, is the newly discovered star a younger star? explain your answer.