Overview
This lecture explains how to draw a Bohr diagram for silicon, focusing on the arrangement of protons, neutrons, and electrons.
What is a Bohr Diagram?
- A Bohr diagram visually represents electrons orbiting the nucleus of an atom.
- It is based on the Bohr model, which approximates electron arrangement in energy levels (shells).
- The outermost shell is called the valence shell.
Steps to Draw a Bohr Diagram for Silicon
- Begin by drawing the nucleus, which contains protons and neutrons.
- Silicon has 14 protons (atomic number 14) and 14 neutrons (mass number rounded minus protons).
- Write the number of protons and neutrons inside the nucleus for clarity.
- Draw the first ring around the nucleus; place 2 electrons on it (first shell capacity).
- Draw a second ring; it holds 8 electrons (second shell capacity).
- Draw a third ring; place the remaining 4 electrons on it (third shell).
- Space the electrons evenly, ideally in pairs for symmetry.
Checking Your Work
- Count all drawn electrons to ensure there are 14, equal to silicon’s atomic number.
Key Terms & Definitions
- Bohr diagram — a diagram showing electrons in shells around an atom’s nucleus.
- Nucleus — the center of the atom containing protons and neutrons.
- Proton — a positively charged particle in the nucleus.
- Neutron — an uncharged particle in the nucleus.
- Electron — a negatively charged particle that orbits the nucleus in shells.
- Atomic number — the number of protons in an atom.
- Mass number — the total number of protons and neutrons in an atom.
Action Items / Next Steps
- Practice drawing Bohr diagrams for other elements using their atomic number and mass number.
- Review the definition and purpose of valence shells.