Isotopes and Relative Atomic Mass

Question 1

What are isotopes?

Answer 1

Different forms of the same element, which have the same number of protons but a different number of neutrons.

Question 2

In terms of the mass and atomic numbers, what are isotopes?

Answer 2

Different forms of the same element, with the same atomic number but different mass numbers.

Question 3

What is the relative atomic mass (Ar)?

Answer 3

The average mass of one atom of an element, compared to 1/12 of the mass of one atom of carbon-12.

Question 4

What number shows the relative atomic mass of an element on the periodic table?

Answer 4

The bigger one (the top number).

Question 5

If an element has only one isotope, what can you say about its relative atomic mass?

Answer 5

It will be the same as the mass number.

Question 6

If an element has more than one isotope, what can you say about its relative atomic mass?

Answer 6

It will be the average of the mass numbers of all the different isotopes, taking into account how much there is of each one.

Question 7

How can you calculate the Ar from isotopic abundances?

Answer 7

1) Multiply the relative isotopic mass by its isotopic abundance, and add up the results.
2) Divide by the sum of the abundances (if the abundances are given as percentages, this will be 100).