Formulas

Atomic Structure

Atoms consist of a small dense positively charged nucleus and negatively charged electrons in orbit around the nucleus.

A nucleus is composed of:

— Positively Charged Proton — Neutrally Charged Neutrons

Hence, a nucleus has an overall positive charge. While electrons has a negative charge.

The Nucleus contains Proton & Neutron.

Relative Charge & Mass

• Protons have a positive charge; mass of 1 amu.
  • +1 ( 1 amu )
• Electrons have a negative charge; mass of $\frac{1}{2000}$ amu.
  • -1 ( $\frac{1}{2000}$ amu )
• Neutrons have no charge; mass of 1 amu.
  • 0 ( 1 amu )

Nuclide Notation

• Atomic symbols are written in a specific notation called nuclide notation.
  • The top number A represents the nucleon / mass number

    • of Protons + # of Neutrons

  • The lower number Z represents the proton / atomic number

    • of Protons

Isotopes

Isotopes are atoms of the same element that have an equal number of protons but a different number of neutrons. This means that each element can have more than one isotope.

• Isotopes tend to be more unstable due to their imbalance of protons and neutrons
  • This means they're more likely to decay.

So Isotopes, the same elements,

the nucleon / mass number is different, because the neutron is different;

the atomic / proton number will stays the same, because there’s no change for Protons.