atomic number
Number of protons in the nucleus of an atom. It is equal to the positive charge on the nucleus. In a neutral atom, it is also equal to the number of electrons surrounding the nucleus. The chemical elements are arranged in the periodic table of the elements according to their atomic number. Nuclear notation is used to label an atom according to the composition of its nucleus.
© RM 2012. Helicon Publishing is division of RM.
Encyclopaedia search
Advertisement starts
Advertisement ends
Advertisement starts
Advertisement
Advertisement ends
Country search
Dictionary search
Iceland flag
Health search
Advertisement starts
Advertisement ends
Skip to page content | Text onlyGraphical version of this page
TalkTalk Quicklinks. Please visit our Accessibility Page for a list of the Access Keys you can use to find your way around the site, skip directly to the main navigation, to the page content, or to more links within homepage.
Page Footer
Access keys
You will need to use different key combinations in order to use access keys depending on your internet browser, find out which on our accessibility page.
- (0) Navigate to Accessibility page.
- (1) Navigate to Home page.
- (2) Navigate to My email.
- (3) Navigate to My Account.
- (4) Navigate to Site Map page.
- (5) Navigate to Contact us page.
- (6) Navigate to Members channel.
- (7) Navigate to Services channel.
- (8) Navigate to News & Info channel.
- (9) Navigate to Entertainment channel.
- ([) Skip down to the Primary navigation block.
- (]) Skip down to the more links within this section block.
- (=) Bypass all navigation and jump to the content.
- (x) Text only version of this page.
