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I believe the answer is the third option. Hope this helps! Please tell me if I am wrong or if there was an error in my answer... also sorry this answer is late.
1) Carbon-13:
Proton-6 Neutron-7 Electron-6
2)Atomic mass of element X:
(55*10+56*20+57*70)/100=56.6
Answer: The substance is neutral
Explanation:
If you place red litmus paper into a basic substance, it turn's blue. When it comes in contact with an acidic or neutral substance, it doesn't change colour it remains red.
Blue litmus paper in acid turns red when placed in a basic or neutral solution it remains blue. From this it can be concluded that the solution is neutral.
Bro honestly I don’t understand either