Explanation

Isotopes are atoms with different atomic masses that have the same atomic number.

The atoms of different isotopes are atoms of the same chemical element; they differ in the number of neutrons in the nucleus.

Isotopes:

• The isotopes are a group of atoms that have the same atomic numbers but different mass numbers.
• That means all isotopes of an element have the same number of protons in their atomic nuclei and the same number of electrons in the electron cloud surrounding the nucleus.

Difference between isotopes

• Isotopes differ in the total number of neutrons present in their respective atomic nuclei.
• Thus they have different mass numbers.
• Different isotopes of the same element are having different masses.
• Protium (1 proton,1 electron, and no neutrons), Deuterium (1 proton, 1 electron, and 1 neutron), and Tritium (1 proton, 1 electron, and 2 neutrons) are examples of isotopes of Hydrogen.

Explanation

Carbon dioxide (CO₂) is commonly used in fire extinguishers because it helps to displace oxygen and smother the fire, preventing it from spreading.

It is particularly effective for electrical fires and fires involving flammable liquids.

Explanation

The percentage of oxygen in the air is about 20.95%.

The air is made up of many gases, including oxygen, nitrogen, argon, and carbon dioxide

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Nitrogen

Nitrogen is the most abundant gas in the air, making up about 78% of it. 

Argon

Argon is the third most abundant gas in the air, making up about 0.93% of it. 

Carbon dioxide

Carbon dioxide is present in trace amounts in the air, making up about 0.04% of it. 

Explanation

Symbol: Hg

Atomic number: 80

Melting point: -38.83 °C

Atomic mass: 200.59 u

Explanation

LPG (Liquefied Petroleum Gas) mainly consists of hydrocarbons like propane and butane.

These are gases composed of hydrogen and carbon atoms.

It is used as fuel for cooking and heating.