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
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.
To identify an element that has the same number of valence electrons as a magnesium atom but is in a lower energy level, we first need to determine the number of valence electrons in a magnesium atom.
Magnesium is located in Group 2A (or Group 2) of the periodic table. Elements in this group have two valence electrons.
Now we need to find an element that is in a lower energy level than magnesium but has two valence electrons.
By referring to the periodic table, we can see that elements in the period directly above magnesium (Period 3) will be in a lower energy level.
Examining Period 3, we identify the element in Group 1A (Group 1) of Period 3, which is sodium (Na). Sodium has one fewer energy level (Period 2) than magnesium, but it also has two valence electrons (like magnesium).
Therefore, sodium (Na) is the element that has the same number of valence electrons as a magnesium atom but is in a lower energy level.
To identify an element that has the same number of valence electrons as a magnesium atom but is in a lower energy level, we need to understand the electronic configuration of magnesium and look for an element in the periodic table with a similar configuration but in a lower energy level.
Magnesium (Mg) has an atomic number of 12, meaning it has 12 electrons. The electronic configuration of magnesium is 1s² 2s² 2p⁶ 3s².
Valence electrons are the electrons in the outermost energy level of an atom. In the case of magnesium, the valence electrons are the two electrons in the 3s orbital. We are looking for an element with the same number of valence electrons but in a lower energy level.
By observing the periodic table, we can see that elements in the same group (vertical column) have the same number of valence electrons. Magnesium is in group 2, so other elements in this group will have two valence electrons as well. However, we need an element that has the same number of valence electrons in a lower energy level.
To find an element with these characteristics, we need to move to the previous period (horizontal row) in the periodic table. This is because elements in the same group will have the same number of valence electrons, but elements in the previous period will have those valence electrons in a lower energy level.
By moving to the previous period, we find the element Beryllium (Be) with an atomic number of 4. The electronic configuration of beryllium is 1s² 2s². Beryllium has two valence electrons in the 2s orbital, just like magnesium, but these electrons are located in a lower energy level.
Therefore, the element that has the same number of valence electrons as a magnesium atom but is in a lower energy level is Beryllium (Be).