Respuesta :
Answer:
The number of periods shows you the number of _______
Electron Shell
Explanation:
Modern periodic table is divided into Groups and Periods.
A period is the horizontal row of the periodic table. There are seven periods in the periodic table.
It describes the following :
- The period in which a particular element found will show its electron shell
- The first period has Hydrogen and Helium = 1 - shell
- The second Period has Lithium to neon = 2- shells
A group is the vertical column of the periodic table . There are 18 groups in total.
It describes the following :
The group number of the element is same as the number of electrons in the outermost shell.
The element having group 1 has = 1 electron in outer shell (example Na, K)
The element having group 2 has = 2 electron in outer shell (example Ca, Mg)
The element having group 0 has = full outer shell (example Ne Xe). these are also known as noble gases
