Explanation

• Electrical conductivity means how easily a material allows electric current to pass through it.
• Among common metals, silver has the highest electrical conductivity.

Additional information:

• Silver: 100 (highest)
• Copper: 97 (very close second)
• Gold: 76
• Aluminum: 60
• Iron: ~17 (low compared to above metals)

Last verified on 17-05-2026

Explanation

• Metals allow electricity to pass through them easily.
• Among all metals, silver has the highest electrical conductivity.
• Copper and gold are also very good conductors.
• Silver is widely used in high-precision electrical applications.
• Copper is commonly used in wiring due to cost-effectiveness.

Last verified on 16-05-2026

Explanation

• An abundant component in Earth's atmosphere is nitrogen, about 78% of the air.
• The second most abundant gas is oxygen, which makes up about 21% of the air.
• Hydrogen and carbon dioxide are both present in the air, but in much smaller amounts than nitrogen and oxygen.

Last verified on 16-05-2026

Explanation

• Isotopes of an element have the same number of protons.
• They differ in number of neutrons, which changes mass number.
• Chemical properties remain almost the same due to same protons.

Last verified on 14-05-2026

Explanation

• Atoms are made of subatomic particles: protons, neutrons, and electrons.
• Mass number represents the total number of heavy particles in nucleus.
• Only protons and neutrons contribute to atomic mass.

Last verified on 14-05-2026

Explanation

• Atoms that have the same number of neutrons but different atomic numbers are called isotones.
• They belong to different elements because their proton numbers are different.

Additional information:

• The word “isotone” comes from Greek meaning “equal tension.”
• Isotopes belong to the same element, while isotones belong to different elements.

Last verified on 13-05-2026

Explanation

• An atom is electrically neutral when positive and negative charges are equal.
• Protons carry positive charge, while electrons carry negative charge.
• If both are equal in number, the total charge becomes zero.

Additional information:

• The nucleus contains protons and neutrons.
• Electrons move around the nucleus in energy shells.

Last verified on 13-05-2026

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