Barium at Chemical Elements.com  

Basic Information


Name: Barium
Symbol: Ba
Atomic Number: 56
Atomic Mass: 137.327 amu
Melting Point: 725.0 °C (998.15 °K, 1337.0 °F)
Boiling Point: 1140.0 °C (1413.15 °K, 2084.0 °F)
Number of Protons/Electrons: 56
Number of Neutrons: 81
Classification: Alkaline Earth
Crystal Structure: Cubic
Density @ 293 K: 3.51 g/cm3
Color: Silver


Atomic Structure

[Bohr Model of Barium]  
Number of Energy Levels: 6

    First Energy Level: 2
    Second Energy Level: 8
    Third Energy Level: 18
    Fourth Energy Level: 18
    Fifth Energy Level: 8
    Sixth Energy Level: 2

Isotopes

Isotope Half Life
Ba-130 Stable
Ba-131 11.7 days
Ba-132 Stable
Ba-133 10.5 years
Ba-133m 1.6 days
Ba-134 Stable
Ba-135 Stable
Ba-135m 1.2 days
Ba-136 Stable
Ba-137 Stable
Ba-137m 2.6 minutes
Ba-138 Stable
Ba-139 1.4 hours
Ba-140 12.8 days
Ba-141 18.3 minutes
Ba-142 10.7 minutes

Facts


Date of Discovery: 1808
Discoverer: Sir Humphrey Davy
Name Origin: From the Greek word barys (heavy)
Uses: Medical applications, among others
Obtained From: barytine, whiterite