Atomic Structure Fundamentals
This section delves into the basic components of atoms and their structure, essential for understanding Atomic Structure GCSE Chemistry Notes.
The atom is incredibly small, with a radius of 1x10^-10m or 0.1 nm. At its core, the nucleus is even tinier, less than 1/10000 of the atom's radius, measuring about 1x10^-14m.
The nucleus contains protons (positively charged) and neutrons (neutral). Surrounding the nucleus are electrons, arranged in energy levels. These energy levels increase in energy as they move further from the nucleus.
Highlight: Electrons can move between energy levels by absorbing or emitting electromagnetic radiation.
An element's atomic number indicates the number of protons, while its mass number represents the total number of protons and neutrons.
Example: Sodium (Na) with atomic number 11 and mass number 23 has 11 protons, 12 neutrons, and 11 electrons.
Isotopes are atoms of the same element with different numbers of neutrons, while ions are atoms that have gained or lost electrons, acquiring an electric charge.
The historical development of atomic models is crucial in understanding our current knowledge:
- Democritus: Proposed indivisible particles separated by empty space.
- John Dalton: Introduced the concept of atoms as solid spheres.
- J.J. Thomson: Discovered electrons and proposed the "plum pudding" model.
- Ernest Rutherford: Conducted the gold foil experiment, leading to the nuclear model.
- Niels Bohr: Introduced the concept of electron shells.
- James Chadwick: Discovered neutrons.
Vocabulary: The Rutherford gold foil experiment involved firing alpha particles at a thin gold foil, leading to the discovery of the atomic nucleus.
