Which of the following is the main component of natural gas? MCQ with Answer and Explanation

Explanation:
Chemical bonds are attractive forces between atoms due to electron interaction—ionic (transfer), covalent (sharing), metallic, etc. These bonds hold atoms together in molecules or crystals. Nuclear force holds protons and neutrons in nucleus. Gravitational and magnetic forces are negligible at atomic scale. Bond energy determines stability; stronger bond means more energy required to break.

Explanation:
Burning of magnesium ribbon produces a new substance, magnesium oxide (MgO), and releases heat and light, which are indicators of a chemical change. Melting, dissolving, and boiling are physical changes because the chemical composition remains unchanged. Chemical changes are generally irreversible.

Explanation:
Joseph Proust proposed the law of definite proportions (constant composition) – a given compound always contains the same elements in the same proportion by mass. Dalton's theory explained it. Lavoisier gave law of conservation of mass. Rutherford discovered nucleus.