Explanation

• Isotones are atoms of different elements having the same number of neutrons.

• Their atomic numbers are different but neutron numbers remain equal.

• Example: Carbon-14 and Nitrogen-15 both have 8 neutrons.

• Isotones may have different chemical properties because they belong to different elements.

• The term “isotone” was introduced in nuclear chemistry studies.

Last verified on 09-05-2026

Explanation

• Almost all the mass of an atom is concentrated in its nucleus.
• The nucleus contains protons and neutrons, which are much heavier than electrons.
• Electrons revolve around the nucleus but contribute very little to atomic mass.
• The nucleus is located at the center of the atom.
• Ernest Rutherford discovered the nucleus through the gold foil experiment in 1911.

Last verified on 09-05-2026

Explanation

• Atoms with the same atomic number but different mass numbers are called isotopes.
• Atomic number depends on the number of protons.
• Mass number depends on protons + neutrons.
• So, difference in mass number comes from variation in neutrons.
• Isotopes have similar chemical properties but different physical properties.

Last verified on 08-05-2026

Explanation

• Natural gas contains about 80% to 95% methane.
• It is a hydrocarbon fuel.
• It is the chief (major) component of natural gas.
• It is also a greenhouse gas.
• Chemical formula: CH₄
• It is a clean-burning fuel used in daily life.

Last verified on 07-05-2026

Explanation

• Isobars are atoms of different elements.
• They have same mass number but different atomic number.
• They show different chemical properties but same nuclear mass.
• Example: Argon-40 and Calcium-40 both have mass number 40 but different atomic numbers.

Last verified on 07-05-2026