Chemistry Notes: Atomic Structure and Electron Configuration
What is an Atom?
Atoms are the fundamental building blocks of matter, constituting everything around us.
A molecule comprises two or more atoms held together by chemical bonds.
A compound is a substance formed by two or more different types of atoms.
Atoms consist of a nucleus containing protons and neutrons, with electrons orbiting the nucleus.
Atomic Number, Symbol, Name, and Atomic Mass
An example element is given as Boron:
- Atomic Number: 5
- Symbol: B
- Name: Boron
- Atomic Mass: 10.811
Protons, Neutrons, and Electrons
Protons
- Charge: Positively charged
- Location: Nucleus
- Determination: Atomic number
Neutrons
- Charge: No charge (Neutral)
- Location: Nucleus
- Determination: Mass number - atomic number
Electrons
- Charge: Negatively charged
- Location: Orbiting the nucleus
- Determination: Atomic number
Electron Configuration
- 1st shell: Holds a maximum of 2 electrons
- 2nd shell: Holds a maximum of 8 electrons
- 3rd shell: Holds a maximum of 8 electrons
The electron configuration is determined based on the atomic number. For instance, an element with 17 electrons will have 17 dots representing its electron configuration.
This configuration follows the 'Octet rule' or the 'Rule of 8'.
The electron distribution follows the sequence 2, 8, 8, 8, …
A hint suggests that information on the element square's side can provide guidance for electron configuration.