Those elements with similar properties are in the same column.
It is not equal because it dose not obey the conservation of mass. 60+25= 85 not 75.
Blocks on the periodic table will not list a mass number of elements in this scenario.
<h3>What is Periodic table?</h3>
This table comprises of elements in order of their atomic number which determines their chemical properties.
It contains the atomic number but however doesn't contain the mass number of the elements.
Read more about Periodic table here brainly.com/question/15987580
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