Among the elements N, O, P, and S, which element or elements
have...

Question

Among the elements N, O, P, and S, which element or elements
have the smallest effect nuclear charge if we use Equation
7.1 to calculate Zeff? Which element or elements have
the largest effective nuclear charge?

Accepted Answer

hey everyone in this example we need to identify which of the given elements has the smallest effective nuclear charge. Based on the equation, effective nuclear charge is equal to atomic number minus s our number of core electrons according to the prompt. So beginning with our adam lithium we're going to use the equation so that we have our effective nuclear charge equal to our atomic number for lithium which we should recall from the periodic table has the atomic number three. So we would plug in three for Z. And then we're going to subtract that from our number of core electrons and lithium. So because we recognize that lithium is in period two of our periodic table, we would count the core electrons as the electrons that come before period two which would be in the one S To sub level where two represents our two core electrons. And so we would say that we have two core electrons for lithium giving us 3 -2 which gives us a difference of one for our effective nuclear charge of lithium. Next we have our atom beryllium, We should recognize that beryllium on our periodic table corresponds to atomic number four. So we would have four equation are effective nuclear charge equal to four minus the number of core electrons in our beryllium atom which is also going to equal The one s to Sublevel as its core electrons. Where two represents our core electrons. So we have 4 -2 and this is going to give us a difference equal to two. Next we have our adam chlorine, we recognize that For the equation effective nuclear charge. We begin with subtracting the atomic number of chlorine. And on our periodic tables we see that chlorine has the atomic number 17. So we would have 17 - the number of core electrons for chlorine. And to determine our number of core electrons for chlorine. We would recall that chlorine is in group seven a of our periodic table which correspond to seven valence or outer electrons. And we should recall that for neutral atoms only our number of electrons is going to equal our atomic number which is also going to equal our number of protons. But the key here is Recognizing that our number of electrons is going to equal our atomic number. So because we know that we have 17 as our atomic number, we would therefore understand that we have 17 electrons for chlorine atom. But because we know that seven of these electrons are valence electrons, we would take 17 -7 and that would leave us with core electrons. Again, this comes from the 17 electrons from our atomic number minus the seven valence electrons To give us a difference of 10 core electrons. And what we're going to have is an effective nuclear charge value equal to 17 -10, which gives us seven. So lastly we have our adam argon, We should recognize that argon corresponds to atomic number 18 and we would calculate its effective nuclear charge By taking its atomic number which again is 18 from the periodic table. And subtracting this from its number of core electrons. So because we recognize that Argon is in group eight, a We would understand that it therefore has eight valence electrons or outer electrons. And so because we recall that the number of electrons is equal to the atomic number for neutral atoms only, which is what we have. We're dealing with neutral argon. We can take our 18 atomic number and understand that we have electrons minus our eight valence electrons or outer electrons would leave us with a difference of 10 core electrons. And so what we would have is 18 -10 which would leave us with an effective nuclear charge value equal to eight. And so to answer this question for the atom with the smallest effective nuclear charge that is going to correspond to lithium because it only had a effective nuclear charge equal to a value of one. So we would say that lithium has the smallest value for effective nuclear charge. And this is going to be our final answer to complete this example. So I hope that everything I explained was clear. If you have any questions, please leave them down below. And I will see everyone in the next practice video

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