Along each row of the periodic table,

Along each row of the periodic table, the atomic mass increases from left to right.

Explanation:

The elements in the periodic table are arranged based on rows and periods by increasing atomic number.

The periodic table has rows from left to right and columns from up and down. These rows are called periods and columns are called groups.

The electron organization in an atom explains about the shape and the elements in the same column have similar chemistry. The elements in each column have the same valence shell electron configuration and they have similar properties.