7
The Periodic Table has 7 periods and 18 groups.
the horizontal rows (not groups) are known as periods.
there are 7 periods in the periodic table118
The periodic table has 7 periods on it.
The modern periodic table has seven periods.
a Periodic Table organises the different elements, according to the atoms' mass, type, properties, reactivity etc. See the question about: periodic table patterns
7The periodic table has 7 periods and 18 groups.
The elements on the periodic table are separated into periods based on the number of electron shells they have. Elements in the same period have the same number of electron shells, which influences their chemical properties and reactivity.
Because the elements that have similar properties are arranged in groups - or 'periods'.
Horizontal rows are termed as periods. There are 7 periods in periodic table.
There are 7 periods in the modern periodic table.
6 periods
7 periods.