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Ch.2 Atoms and the Periodic TableWorksheetSee all chapters
All Chapters
Ch.1 Matter and Measurements
Ch.2 Atoms and the Periodic Table
Ch.3 Ionic Compounds
Ch.4 Molecular Compounds
Ch.5 Classification & Balancing of Chemical Reactions
Ch.6 Chemical Reactions & Quantities
Ch.7 Energy, Rate and Equilibrium
Ch.8 Gases, Liquids and Solids
Ch.9 Solutions
Ch.10 Acids and Bases
Ch.11 Nuclear Chemistry
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
The Atom (Simplified)
Subatomic Particles (Simplified)
Ions (Simplified)
Atomic Mass (Simplified)
Atomic Mass (Conceptual)
Periodic Table: Element Symbols
Periodic Table: Classifications
Periodic Table: Group Names
Periodic Table: Representative Elements & Transition Metals
Periodic Table: Elemental Forms (Simplified)
Periodic Table: Phases (Simplified)
Law of Definite Proportions
Atomic Theory
Rutherford Gold Foil Experiment
Wavelength and Frequency (Simplified)
Electromagnetic Spectrum (Simplified)
Bohr Model (Simplified)
Emission Spectrum (Simplified)
Electronic Structure
Electronic Structure: Shells
Electronic Structure: Subshells
Electronic Structure: Orbitals
Electronic Structure: Electron Spin
Electronic Structure: Number of Electrons
The Electron Configuration (Simplified)
Electron Arrangements
The Electron Configuration: Condensed
The Electron Configuration: Exceptions (Simplified)
Ions and the Octet Rule
Ions and the Octet Rule (Simplified)
Valence Electrons of Elements (Simplified)
Lewis Dot Symbols (Simplified)
Periodic Trend: Metallic Character
Periodic Trend: Atomic Radius (Simplified)

The atomic mass of an element can be found on the Periodic Table.

Determining Atomic Mass

Concept #1: The atomic masses of elements can be found on the Periodic Table.

Example #1: Which of the following represents an element from the first column with the greatest atomic mass?

On the Periodic Table, the atomic mass is represented by the number with decimal places.

Practice: Which of the following choices has the greatest atomic mass?

Concept #2: Calculating Atomic Mass

Example #2: Calculate the atomic mass of gallium if gallium has 2 naturally occurring isotopes with the following masses and natural abundances:

Ga-69          68.9256 amu          60.11%
Ga-71           70.9247 amu           39.89%

Practice: Only three isotopes of magnesium exist on earth. 24Mg is the most common form at 78.70% natural abundance with a mass of 23.98504 amu, 25Mg has a 10.13% natural abundance, while 26Mg has a natural abundance of 11.17% and a mass of 25.98259 amu. What is the mass of the 25Mg isotope?

Practice: Silver has an atomic mass of 107.868 amu. The Ag-109 isotope (108.905 amu) is 48.16%. What is the amu of the other isotope?