Question Video: Recalling How Many Electrons Metals Tend to Have in Their Outermost Energy Level | Nagwa Question Video: Recalling How Many Electrons Metals Tend to Have in Their Outermost Energy Level | Nagwa

# Question Video: Recalling How Many Electrons Metals Tend to Have in Their Outermost Energy Level Science • First Year of Preparatory School

Fill in the blank: Most metals contain ＿ electrons in their outermost energy level.

04:44

### Video Transcript

Fill in the blank. Most metals contain blank electrons in their outermost energy level. (A) More than four, (B) four, (C) less than four, (D) more than five, (E) less than five.

To answer this question, we need to choose the correct word or phrase to put in the blank to complete the statement. We can see from the answer choices that we need to determine how many electrons metals tend to have in their outermost energy level. Let’s clear the answer choices for now so we can look at where the metals are located on the periodic table.

In this diagram of the periodic table, the metals are shown in pink. We can see that most elements are metals. Excluding the elements that have unknown chemical properties, metals are found in groups 1 through 16. A group on the periodic table is a vertical column. In this video, we will focus only on the metals in groups 1 and 2 and those in groups 13 to 16.

A horizontal row on the periodic table is called a period. In general, elements in the same row have electrons located in the same energy levels. An energy level is a region that is a certain distance from the nucleus of an atom and is where electrons are located. Energy levels are also often called electron shells. The first three energy levels inside atoms are the K, L, and M energy levels. K is the energy level closest to the nucleus.

Let’s find out how many electrons are in the energy levels of the elements in period one and two on the periodic table. Period one contains the elements hydrogen and helium. The electrons of these two elements are found in the K energy level. A hydrogen atom contains one electron, and a helium atom contains two electrons.

The electrons of the elements in period two are found in both the K and L shells. All of the elements in this period have two electrons in the K shell, which is an inner shell. We notice that when we move from left to right across the period, each atom has one more electron in the L shell when compared to the atom before it.

Now, let’s take a look at the elements in period three. All of these elements have two electrons in the first energy level and eight electrons in the second energy level. And just like in period two, the first element has one electron in the outermost energy level and each element that comes after has one more electron in its outermost energy level.

There is also another pattern to notice. Elements that are in the same group or column have the same number of electrons in their outermost energy level. For example, all the elements in group 1 have one electron in the outermost energy level. The pattern continues as we move across the periodic table group by group.

The last group contains the noble gases. Noble gases have full outermost energy levels. Helium’s only energy level has two electrons, but all of the other noble gases below helium have eight electrons in their outer energy level.

We notice that the metals, which are outlined in pink here, have three or less electrons in their outermost energy level. There are many more metals that we are not showing here. But in general, metals like the ones we are discussing in this video have less than four electrons in their outer energy level. The elements boron and silicon, outlined in green, are metalloids. And the elements outlined in orange are nonmetals. The element hydrogen has one electron in its outer energy level. And the element carbon has four electrons in its outer energy level. However, most nonmetals have more than four electrons in their outer energy level.

Now let’s bring the answer choices back up on screen. We’ve learned that most metals have less than four electrons located in their outermost energy level. Therefore, the answer that correctly completes the statement is answer choice (C), less than four.

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