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Periods are the horizontal rows in the periodic table of Mendeleev; this table contain 7 periods.
The rows going across the periodic table are known as periods and contain elements with the same number of electron shells.
Rows are called periods. They contain same number of shells.
There are a total of 18 groups on The Periodic Table of Elements.
Rows in the Periodic Table are called Periods.There are 7 periods in total.All the elements in period have same number of energy levels.
The periods in the periodic table refer to the horizontal rows that indicate the number of electron shells an element's atoms have. There are 7 periods in the periodic table, each corresponding to the number of electron shells found in elements within that period.
A complete periodic table arranged in periods and groups. The symbol of element and atomic number are mentioned.
The periodic table of Mendeleev contain now 118 chemical elements arranged in groups and periods.
4 periods
By atomic number.
Modern periodic table has 7 periods and 18 groups.
Period number describes the total number of shells. There are 7 periods in periodic table.