Atomic number and mass number
The periodic table shows the unique symbol of every element, together with its mass number and atomic number. For example, lithium (Li) has a mass number of 7 and an atomic number of 3
The picture below will help you to remember which number is which.
![A memory aid showing that the mass number is always sown above the atomic number which should be smaller](/images/user/base/Chemistry/2. Atomic Structure/2.2.13 Mass is always bigger memory aid.jpg)
![](/images/user/base/Maths/Logarithms/Reference%20Tables/reference-log-table-1.4df6ee6.jpg)
![](/images/user/base/Maths/Logarithms/Reference%20Tables/reference-log-table-2.d516bb3.jpg)
![](/images/user/base/Maths/Logarithms/Reference%20Tables/reference-anti-log-table-1.b0b0513.jpg)
![](/images/user/base/Maths/Logarithms/Reference%20Tables/reference-anti-log-table-2.f89189d.jpg)