Question

write the chemical symbol for an element belonging to each of the element families in the table below.
element family | example element
noble gas |
alkaline earth |

Explanation:

Step1: Noble Gas Example

Noble gases are elements in Group 18 of the periodic table. A common example is Helium, with the chemical symbol $He$. Other examples include Neon ($Ne$), Argon ($Ar$), etc. We can choose Helium as a representative.

Step2: Alkaline Earth Metal Example

Alkaline earth metals are in Group 2 of the periodic table. A common example is Magnesium, with the chemical symbol $Mg$. Other examples include Calcium ($Ca$), Beryllium ($Be$), etc. We can choose Magnesium as a representative.

Answer:

For the "noble gas" family, an example element's chemical symbol is $\boldsymbol{He}$ (or $Ne$, $Ar$, etc.).
For the "alkaline earth" family, an example element's chemical symbol is $\boldsymbol{Mg}$ (or $Ca$, $Be$, etc.).