The element with atomic number 17 belongs to which group and period? MCQ with Answer and Explanation

Explanation:
Methane (CH₄) is a potent greenhouse gas, absorbing infrared radiation. Oxygen and nitrogen are diatomic and do not absorb IR. Argon is a noble gas, inert. Greenhouse gases include CO₂, CH₄, N₂O, CFCs, H₂O vapor.

Explanation:
Acid rain results from SO₂ and NOₓ (from burning fossil fuels) reacting with water vapor to form sulfuric and nitric acids. Normal rain is slightly acidic (pH ~5.6) due to CO₂ forming carbonic acid, but acid rain has pH < 5.6. Effects include corrosion of monuments (Taj Mahal), damage to aquatic life, and soil acidification. CO₂ causes global warming, not primarily acid rain.

Explanation:
Atomic number (Z) is the number of protons in the nucleus, which defines the identity of the element. In a neutral atom, the number of electrons equals Z. Neutrons contribute to mass number but not atomic number. Isotopes have same Z but different number of neutrons. Nucleons are total protons + neutrons = mass number. The modern periodic table is based on atomic number.