(d) An atom of magnesium can be represented by the symbol ²⁴₁₂Mg.
Use numbers to complete these statements about this atom.
(iii) The electronic configuration of this atom is ...............................

📝 Detailed explanation

To determine the electronic configuration, we first look at the atomic number (the bottom number), which is 12. In a neutral atom, the number of electrons is equal to the atomic number. Therefore, magnesium has 12 electrons.
(iii) The electronic configuration of this atom is 2.8.2
Electrons fill the shells in a specific order:
First shell: can hold a maximum of 2 electrons.
Second shell: can hold a maximum of 8 electrons.
Third shell: holds the remaining electrons.
Because there are 2 electrons in the outer shell, magnesium is in Group 2 of the Periodic Table. Because it has 3 occupied shells, it is in Period 3.