The main constituent of biogas is: MCQ with Answer and Explanation

Explanation:
Mass number = protons + neutrons = 6 + 8 = 14. This corresponds to carbon-14 isotope. Atomic number = 6 (carbon).

Explanation:
Radioactive decay is a spontaneous process where an unstable atomic nucleus loses energy by emitting radiation. Since it involves the emission of particles (protons, neutrons, electrons) from the nucleus, it fundamentally alters the nucleus, making it a nuclear, not chemical, process.

Explanation:
The modern periodic law, established by Henry Moseley, states that the properties of elements are periodic functions of their atomic numbers. Mendeleev’s original table was based on atomic mass, but the modern version uses atomic number which resolves anomalies like Ar (Z=18, mass 40) and K (Z=19, mass 39).