Periodic trends

Atomic Size Trends

• General Trends

  • Atomic size increases from top to bottom in a group.

  • Atomic size decreases from left to right across a period.

Ionic Trends

• Ionic Size

  • Cations (positive ions) are smaller than their parent atoms.

  • Anions (negative ions) are larger than their parent atoms.

  • Ionic size increases from top to bottom in a group and decreases from left to right across a period.

Ionization Energy Trends

• Definition: Energy required to remove an electron from an atom.

• General Trends:

  • Ionization energy decreases from top to bottom in a group.

  • Ionization energy increases from left to right across a period.

Electronegativity Trends

• Definition: Ability of an atom to attract electrons in a compound.

• General Trends:

  • Electronegativity decreases from top to bottom in a group.

  • Electronegativity increases from left to right across a period.

  • Notable Elements:

    • Fluorine: Highest electronegativity (4.0)

    • Cesium: Lowest electronegativity (0.7)

Key Concepts Recap

• Atomic size, ionic size, ionization energy, and electronegativity are important trends in the periodic table.

• These properties are influenced by nuclear charge and electron shielding.