Atoms and atomic structure
What is an Atom Like?
Atoms are the "building blocks" of everything. If you cut a piece of gold into smaller and smaller pieces, the smallest piece that is still gold is an atom.
Modern science shows that an atom is made of three tiny subatomic particles:
1. Protons: Located in the center; they have a positive (+) charge.
2. Neutrons: Also in the center; they have no charge (neutral).
3. Electrons: Tiny particles that zip around the center; they have a negative (-) charge.
Arranging the Electrons: Shells and Orbits:
Electrons don't just fly around randomly; they live in specific energy levels called shells.
• The 2-8-8 Rule: For the first 20 elements, the shells fill up in a specific pattern. The first shell (closest to the nucleus) can only hold 2 electrons. The second can hold 8, and the third can also hold 8.
• Electronic Structure: This is just a way of writing where the electrons are. For example, Sodium has 11 electrons. Its structure is 2, 8, 1. Atomic number VS atomic mass:
A. Atomic Number (The ID)
• What it is: The number of protons in the nucleus.
• What it does: It tells you which element the atom is (e.g., Atomic Number 1 is always Hydrogen).
• The Rule: It never changes for a specific element.
B. Mass Number (The Weight)
• What it is: The number of protons + neutrons added together.
• What it does: It tells you the total "mass" of the nucleus.
• The Rule: This can change if the atom has more or fewer neutrons (isotopes).