25% of chlorine atoms are 37 Cl and 75% are 35 Cl. The weighted mean mass of chlorine is 35.5. The relative atomic mass of an element is a weighted mean mass of the isotopes of an element compared ...

Scientists use the periodic table to quickly refer to information about an element, like atomic mass and chemical symbol. The periodic table’s arrangement ... the periodic table has evolved to reflect ...

Accompanying Lesson Plan: Lesson 3.2: Finding Volume—The Water Displacement Method The chart shows that atomic size and mass for the first 20 elements in the periodic table. The size of the atoms and ...