Structure of the Atom and the Periodic Table
Atomic Structure · Atomic Structure and Periodicity
Syllabus tag: KCSE | Chemistry | Form 2 | Topic 6 Structure of the Atom and the Periodic Table
Lesson objectives
By the end of this topic, you should be able to:
- Describe the structure of the atom and define atomic and mass number.
- Write electron arrangements and relate them to position in the periodic table.
- Explain isotopes and calculate relative atomic mass.
- Describe the periodic table and the trends across periods and down groups.
Summary
An atom has a central nucleus of protons and neutrons, surrounded by electrons in energy levels. The atomic number (Z) is the number of protons, and the mass number (A) is protons plus neutrons. The periodic table arranges elements by increasing atomic number, and group number equals the number of outer electrons.