Understanding Atoms and the Periodic Table

Atoms are the fundamental building blocks of matter. Each atom consists of protons, neutrons, and electrons, with their arrangements and behaviors dictating chemical properties.

The periodic table is more than just a list—it's a map of elements, showing recurring trends (periodicity) in properties like atomic radius, ionization energy, and electronegativity. Recognizing these patterns is key for problem-solving on the GRE Chemistry test.

Key Points

• Protons define the element and its atomic number.
• Neutrons contribute to atomic mass and isotopic differences.
• Electrons are found in shells and subshells, and their arrangements determine chemical behavior.
• Periodic trends such as increasing electronegativity across a period or decreasing atomic radius down a group help predict reactivity.

Real-World Impact

Understanding atomic structure underpins technologies like MRI scanners (which rely on nuclear spin properties) and the design of new materials.