Using the periodic table, identify an element that has the same number of valence electrons as a magnesium atom but is in a lower energy level. Explain your reasoning

Answer 1

An element with the same number of valence electrons as a magnesium atom but in a lower energy level is beryllium (Be).

Magnesium (Mg) is in period 3 of the periodic table, which means it has three energy levels. It has a total of 12 electrons, with two electrons in the first energy level, eight electrons in the second energy level, and two valence electrons in the third energy level.

Beryllium (Be), on the other hand, is in period 2 of the periodic table, indicating that it has two energy levels. It has a total of four electrons, with two electrons in the first energy level and two valence electrons in the second energy level.

Both magnesium and beryllium are in the same group (Group 2) of the periodic table, also known as the alkaline earth metals. Elements in this group have two valence electrons. While magnesium is in a higher energy level due to being in period 3, beryllium also has two valence electrons but in a lower energy level since it is in period 2.