What is atom and molecules for Class 9?
Answer: The smallest particle of matter, which can take part in a chemical reaction is called atom. Question 5. Define molecule. Answer: The smallest particle of an element or compound which can exist independently is called molecule.
What is atomic mass unit Class 9 learn CBSE?
Answer. One atomic mass unit is a mass unit equal to exactly one twelfth (1/12th) the mass of one atom of carbon -12.
What are molecules questions and answers?
A. A group of two or more atoms that are chemically bonded together or is tightly held together by attractive forces.
What is the molecule class 9?
A group of two or more than two atoms of the same or different elements that are chemically bonded together is called a molecule. For example: Two atoms of hydrogen (H2) and one atom of oxygen (O2) react with each other and form one molecule of water.
Who discovered atom?
The idea that everything is made of atoms was pioneered by John Dalton (1766-1844) in a book he published in 1808. He is sometimes called the “father” of atomic theory, but judging from this photo on the right “grandfather” might be a better term.
What is an atom Class 9 short answer?
Answer: The definition of an atom is the smallest component of an element, characterized by a sharing of the chemical properties of the element and a nucleus with neutrons, protons and electrons.
Why is it not possible to see an atom?
Answer: An atom cannot be visible to the naked eyes because, Atoms are miniscule in nature, measured in nanometres. Except for atoms of noble gasses, they do not exist independently.
How are atoms formed?
Atoms were created after the Big Bang 13.7 billion years ago. As the hot, dense new universe cooled, conditions became suitable for quarks and electrons to form. Quarks came together to form protons and neutrons, and these particles combined into nuclei.
What is called atom?
An atom is the basic building block of chemistry. It is the smallest unit into which matter can be divided without the release of electrically charged particles. It also is the smallest unit of matter that has the characteristic properties of a chemical element.