because they are too long to fit and they belong after the 56 element that means that if they are in the same column they have similar properties
The rows in the periodic table are called periods. There are 7 periods in periodic table.
There are 7 periods in the modern periodic table.
rows. the vertical columns are called periods
They are the horizontal rows in the periodic table
The periodic table has 7 rows and 32 columns.
The horizontal rows on the periodic table are called periods.
The horizontal rows are periods on periodic table. There are 7 horizontal rows in modern periodic table.
The rows are used to study the change in trends. There are 7 periods in periodic table.
Horizontal rows on the Periodic Table of Chemical Elements are called periods.
Horizontal rows in Periodic Table are called Periods
Horizontal rows are called groups. Groups are formed according to the atomic number.
The two names for horizontal rows on the periodic table are periods and series.