Respuesta :
Answer : The correct options are,
They have the same number of electron shells.
They transition from a metal to noble gas.
Explanation :
Periods : A row in the periodic table is know as periods.
The common features about the elements of a period are :
- Each periods has elements with the same number of electron shells or energy levels or shell.
- They transition from metal to noble gas that means they move from metal to non-metal and then non-metal to noble gas.
Groups : A column in the periodic table is know as groups.
The common features about the elements of a same group are :
- Each groups has elements with the same number of valance electrons.
- The elements in the same group have similar chemical properties.
- The elements in the same group have similar physical properties.
Hence, the correct options are,
They have the same number of electron shells.
They transition from a metal to noble gas.
Explanation:
In a period, the row number of elements determine the number of shells present in the elements.
For example, elements present in row 3 will have n = 3.
This means that each element of row 3 will have 3 shells. Like sodium is a row 3 element and its electronic configuration is [tex]1s^{2}2s^{2}2p^{6}3s^{1}[/tex].
Hence, here n = 3.
Also, on moving left to right across a period elements are transitioning from metals to noble gases.
On the other hand, elements present in the same group will have same number of valence electrons.
For example, fluorine and chlorine are both halogen atoms and both of them have only 1 valence electron.
Thus, we can conclude that common about the elements of a period are as follows.
- They have the same number of electron shells.
- They transition from a metal to noble gas.
