Define a mass number ?

Define atomic number and mass number .

Define atomic number and mass number. How can you represent an atom by using atomic number and mass number? Give two examples.

Define atomic number of an element. How is it related to the mass number ?

Define atomic number.

Define isotopes why do isotopes have same atomic number but differente mass numbers? Explain with the help an example.

Define the terms atomic number and mass number how are they related to each other? In which case the atom of the element has same number of protons and electrons?