Video: Deducing the Number of Electrons in a Specified Energy Level

The diagram shows electrons in different energy levels in an atom. How many electrons are there in the first energy level? How many electrons are there in the second energy level? How many electrons does the atom have in total?

02:10

Video Transcript

The diagram shows electrons in different energy levels in an atom. How many electrons are there in the first energy level? How many electrons are there in the second energy level? How many electrons does the atom have in total?

Okay, so in order to answer this question, we need to understand what this diagram is showing us here. So we can understand that this is a diagram of an atom showing the electrons in different energy levels. And so at the center of the atom, we know that there must be a nucleus. This is represented by the pink blob. And the nucleus contains the protons and neutrons in the atom. However, the electrons actually surround the nucleus. And so they are represented by these little blue dots.

Now, the black lines on which these blue dots are found are the energy levels in the atom. And we can recall that we label energy levels with numbers, starting with the energy level nearest to the nucleus, so that’s this one here. We call that energy level number one. And then we systematically increase the numbering on the energy levels as we move further away from the nucleus. So the energy level we’ve pointed to now is called energy level number two. And in this diagram, we’ve only been shown to energy levels. So we don’t need to worry about numbering any other ones. And at this point we can start looking at the questions we’ve been asked.

The first one asks, how many electrons are there in the first energy level? Well, like we said, the circle closest to the nucleus represents the first energy level and in this level we can see that there are one, two electrons. And hence, our answer to this first question is two. Moving onto the second question then, this one asks us, how many electrons are there in the second energy level? And we can recall that the second energy level is the one that’s second closest to the nucleus, so, in this case, the outer energy level in the diagram. And so all we need to do is to count the number of electrons the number of blue dots in this energy level. And that number is one, two, three, four. And so we can say that there are four electrons in the second energy level.

Moving on to the final question then, how many electrons does the atom have in total? Well, regardless of how these electrons are distributed in the energy levels, we know that the atom overall contains one, two, three, four, five, six electrons. And hence, that is the answer to our final question.

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.