Atomic Structure Notes
- An element is represented using a one or two letter abbreviation. The first letter is always capitalized. H, He, Cu
- An element's atomic number, the number of protons (p+) is represented with a numeric subscript. 1H 2He 29Cu
- An element's mass number = number of protons (p+) plus neutrons (no). It is represented with a numeric superscript. 1H 4He 64Cu
- These can be combined to form shorthand symbology for representing an element's atomic structure: 11H 42He 6429Cu
How do we find the number of proton, neutrons and electrons?
- Normally an atom has no net charge.
- The positive charges and its negative charges balance.
- Number of protons (p+) = Number of electrons (e-).
- Carbon's atomic number = 6 so the number of p+= 6.
- Since carbon has 6 p+, it also has 6 e-
- The number of neutrons (no) is the mass number - number of protons.
- For 126C, the number of no= 12 - 6 = 6.
- For 136C, the number of no= 13 - 6 = 7.
- For 146C, the number of no= 14 - 6 = 8.
|Natural Carbon Isotopes||126 C||136 C||146 C|
|Number of protons (p+ )||6||6||6|
|Number of electrons (e- )||6||6||6|
|Number of neutrons (no )||6||7||8|
|Atomic mass number||12||13||14|
|Average Atomic mass for C||12.01||12.01||12.01|