If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Skip to main content
Subjects
  • Math by subject
    • Early math
    • Arithmetic
    • Pre-algebra
    • Algebra 1
    • Geometry
    • Algebra 2
    • Trigonometry
    • Precalculus
    • Statistics & probability
    • AP Calculus AB
    • AP Calculus BC
    • Multivariable calculus
    • Differential equations
    • Linear algebra
  • Math by grade
    • Kindergarten
    • 1st
    • 2nd
    • 3rd
    • 4th
    • 5th
    • 6th
    • 7th
    • 8th
    • Eureka Math/EngageNY
    • High school
  • Science & engineering
    • Physics
    • AP Physics 1
    • AP Physics 2
    • Cosmology & astronomy
    • Chemistry
    • AP Chemistry
    • Organic chemistry
    • Biology
    • AP Biology
    • Health & medicine
    • Electrical engineering
  • Computing
    • Computer programming
    • Computer science
    • Hour of Code
    • Computer animation
  • Arts & humanities
    • World history
    • US history
    • AP US History
    • Art history
    • Grammar
  • Economics & finance
    • Microeconomics
    • Macroeconomics
    • Finance & capital markets
  • Test prep
    • SAT
    • MCAT
    • GMAT
    • IIT JEE
    • NCLEX-RN
  • College, careers, & more
    • College admissions
    • Careers
    • Personal finance
    • Entrepreneurship
Search
DonateSign in / Sign up
Search for subjects, skills, and videos
Main content
Chemistry

Periodic table

Lessons
Introduction to the periodic table
Periodic table trends
Lessons
Introduction to the periodic tablePeriodic table trends
Introduction to the periodic table
Learn
The periodic table - classification of elements
Groups of the periodic table
Counting valence electrons for main group elements
The periodic table - transition metals
Valence electrons and bonding
Practice
Counting valence electrons
7 questions
Periodic table trends
Learn
Atomic radius trends on periodic table
Atomic and ionic radii
Mini-video on ion size
Ionization energy trends
Period trend for ionization energy
First and second ionization energy
Electron affinity: period trend
Electronegativity
Electronegativity and bonding
Metallic nature