Elements of the Periodic Table

Overview

• Atomic Number: Number of protons in an atom, unique for each element.
• Atomic Mass: Primarily determined by protons and neutrons, measured in atomic mass units (amu).
• Isotope: Atoms with the same atomic number but different neutrons.
• Atomic Weight: Weighted average of all naturally occurring isotopes, based on IUPAC's 2021 table.

Table Structure

• Columns include:
  • Atomic Number
  • Symbol
  • Name
  • Atomic Weight
  • Melting & Boiling Points
  • Density
  • Earth's Crust Composition
  • Group Number
  • Electron Configuration
• Groups: 18 standard groups; Lanthanoids (101) and Actinoids (102) marked separately.
• Elements marked with an asterisk () have unstable nuclides and show mass number of the longest-lived isotope.

Notable Elements

• Hydrogen (H): Lightest element, atomic number 1.
• Helium (He): Noble gas, atomic number 2.
• Carbon (C): Basis of organic chemistry, atomic number 6.
• Oxygen (O): Essential for respiration, atomic number 8.
• Iron (Fe): Common metal, atomic number 26.
• Gold (Au): Precious metal, atomic number 79.

Key Concepts

• Electron Configuration: Arrangement of electrons around the nucleus of an atom. Further details available on referenced page.
• Density Abbreviation: Elements with boiling points below 0°C are in g/l, others in g/cm³.
• Earth's Crust Composition: Average values differ regionally, based on Clarke and Washington's 1924 report.

Resources for Further Study

• Periodic Table Elements in Hebrew
• Chemical Evolution of the Universe
• NIST Atomic Reference Data

Citation

• Israel Chemistry Directory. (2025). "Sortable list of elements of the Periodic Table". https://www.science.co.il/elements/