Answer:
Neils Bohr determined that electrons inhabit distinct energy levels.
Explanation:
Answer: The bubbles produced are most likely due to oxygen.
Explanation:
Photosynthesis is a phenomenon in which green plants containing chlorophyll use sunlight as a source of energy to convert carbon dioxide and water to form glucose and oxygen.
The balanced chemical reaction for photosynthesis is:

Thus the bubbles produced are most likely due to oxygen.
Answer:
B) K⁺, Sr²⁺ , O²⁻
Explanation:
Potassium is present in group one. It is alkali metal and have one valance electron.Potassium need to lose its one valance electron and form cation to get complete octet.
That's why it shows K⁺.
Sr is alkaline earth metal. It is present in group two. It has two valance electrons. Strontium needed to lose its two valance electrons and get stable electronic configuration.
When it loses its two valance electrons it shows cation with charge of +2.
Sr²⁺
Oxygen is present in group 16. It has sex valance electrons. It needed two more electrons to complete the octet. That's why oxygen gain two electron and form anion with a charge of -2.
O²⁻
Answer: 43.125g
Explanation:4Na+ O2=2Na2O
Molar mass: 23. 32. 62. React.mass: 92.