Question

periodic table assignment
magnesium is in group □ and period □.
gallium is in group □ and period □.

Explanation:

Step1: Recall Magnesium's position

Magnesium (Mg) has atomic number 12. In the periodic table, group number for alkaline earth metals (Mg is one) is 2, period is 3 (since electrons fill 3 energy levels: \(1s^2 2s^2 2p^6 3s^2\)).

Step2: Recall Gallium's position

Gallium (Ga) has atomic number 31. Electron configuration: \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^1\). Group 13 (since valence electrons in p - block, group = 10 + number of p electrons = 10 + 3 = 13), period 4 (highest energy level n = 4).

Answer:

Magnesium: group 2, period 3; Gallium: group 13, period 4