What is the order of magnitude of mass of one atom ? What are isotopes?

What is the concept of centre of mass ?

State the order of magnitude of duration of a day.

What is order of magnitude of one year in terms of seconds?

What is the magnitude of charge on an electron?

What is an atom and moleule ? What are isotopes?

What is an atom ?

What is order of magnitude? Explain with some examples.

What is the abundance of isotopes ?

What is the mass of one atom of chlorine in grams?

A stone of mass 0.05 kg is thrown vertically upwards. What is the direction and magnitude of net force on the stone during its upward motion?