1.4 Elements, isotopes & relative isotopic mass

chemistry topic 1

What is an isotope?

Isotopes are atoms with the same number of protons (so they are the same element) but a different number of neutrons. Isotopes of an element have the same atomic number but different mass numbers.

Boron has the atomic number 5 and the mass number 11. How many protons, electrons and neutrons does Boron have?

5 protons 5 electrons 6 neutrons

Why is the relative atomic mass not always a whole number?

Different isotopes of the same element have different mass numbers. The relative atomic mass is an average of the masses of all these isotopes.

What two values would be required to calculate the relative atomic mass of chlorine? (higher only)

Mass numbers and relative abundances of all the isotopes of chlorine.