definitions

Key Definitions in Atomic Structure

• Matter

  • Any substance that possesses mass and occupies physical space.

• Element

  • A fundamental chemical substance consisting of atoms that all have the same number of protons, which cannot be broken down into simpler substances by ordinary chemical reactions.

• Proton

  • A positively charged subatomic particle found within the atomic nucleus, possessing a relative charge of $+1$ and a relative mass of $1$.

• Neutron

  • An uncharged subatomic particle residing in the atomic nucleus, possessing a relative charge of $0$ and a relative mass of 1$.\n\n- **Electron** \n - A negatively charged subatomic particle orbiting the atomic nucleus in specific energy levels, possessing a relative charge of -1$and a relative mass of approximately$\frac{1}{1836}.\n\n- **Atomic Number** (Z) \n - The total number of protons found in the nucleus of an atom, defining the identity of a chemical element.\n\n- **Mass Number** (A) \n - The total number of protons and neutrons present in an atom's nucleus, calculated as A = Z + N$, where$N$$ represents the number of neutrons.