Why is the first ionization energy of $"O"$ lower than for $"N"$, but the second ionization energy for $"O"$ higher?

Md Ariful Islam

0 like 0 dislike
1 views
Share with your friends

1 Answers

Md Ariful Islam

Call

Well, I would use to check these. I looked up the first two ionization energies (by typing the atomic symbol) and got...

  • $"IE"_1 ("N") = "14.534 eV"" "" "" ""IE"_1 ("O") = "13.618 eV"$
  • $"IE"_2 ("N") = "29.601 eV"" "" "" ""IE"_2 ("O") = "35.121 eV"$

or...

  • $"IE"_1 ("N") ~~ "1402 kJ/mol"" "" ""IE"_1 ("O") ~~ "1314 kJ/mol"$
  • $"IE"_2 ("N") ~~ "2856 kJ/mol"" "" ""IE"_2 ("O") ~~ "3389 kJ/mol"$

Here, you can see that the first ionization energy of oxygen atom is lower. Consider the electron configurations.

$"N": [He]2s^2 2p^3$

$underbrace(ul(uarr color(white)(darr))" "ul(uarr color(white)(darr))" "ul(uarr color(white)(darr)))$
$" "" "" "color(white)(.)2p$
$ul(uarr darr)$
$color(white)(.)2s$

$"O": [He]2s^2 2p^4$

$underbrace(ul(uarr darr)" "ul(uarr color(white)(darr))" "ul(uarr color(white)(darr)))$
$" "" "" "color(white)(.)2p$
$ul(uarr darr)$
$color(white)(.)2s$

Since oxygen has a paired $2p$ electron, that one will repel the others, making it easier to remove than any of the others.

Easier to remove $->$ lower ionization energy.

The second ionization energy of oxygen is higher than for nitrogen. In principle, they should be the same for two seemingly identical $2p$ electrons, BUT we would neglect an important factor...

It is because oxygen atom is smaller due to a higher effective nuclear charge $Z_(eff) = Z - S$, where $S$ is approximated to be the number of core electrons and $Z$ is the .

$Z_(eff,N) ~~ "7 protons" - "2 core e"^(-) ~~ 5$
$Z_(eff,O) ~~ "8 protons" - "2 core e"^(-) ~~ 6$

So, it is more difficult to remove the electron from the smaller atom, whose electrons are more tightly bound to the nucleus.

Harder to remove $->$ higher ionization energy.

0 like 0 dislike
1 views
Talk Doctor Online in Bissoy App
The temperature at a camp was -4 deg C on Saturday. Sunday morning, the temperature was 3 deg C lower than what it was on Saturday. By Sunday evening, the temperature was 1 deg C lower than what it was that morning. What was the final temperature?

Add the temperatures in the order they were measured. $overbrace(-4^@"C")^color(purple)"Sat"+ overbrace((-3^@"C"))^color(purple)"Sun morn"+overbrace((-1^@"C"))^color(purple)"Sun eve"=-8^@"C"$

1 Answers 1 views
In the ground state, each atom of an element has two valence electrons. This element has a lower first ionization energy than calcium. Where is this element located on the Periodic Table?

It is a period or row that is energy level five or more, below calcium on . Two valence electrons places the element in the alkaline earth family or...

1 Answers 1 views
Magnesium is found to have a higher first ionization energy value than aluminum, how would you explain this exception to the general trend in terms of electron arrangements and attraction/repulsion?

For Mg, $Z$ $=$ $12$. Therefore its electronic configuration is $1s^(2)2s^(2)2p^(6)3s^(2)$; versus Al, $Z$ $=$ $13$; $1s^(2)2s^(2)2p^(6)3s^(2)3p^(1)$. While aluminum metal has extra nuclear charge, $p$ orbitals demonstrably have zero electron...

1 Answers 1 views
Why does a Cs atom have lower ionization energy than a Li atom?

We are looking at the equation: $M(g) rarrM^+(g) + e^-$ Obviously you have to pump in energy. This energy INCREASES across a Period (from left to right) and DECREASES down...

1 Answers 1 views
Why is the first ionization energy of aluminum lower than the first ionization of magnesium?

Electronic configuration of atomic $Mg$: $1s^(2)2s^(2)2p^(6)3s^2$, versus $Al$, $1s^(2)2s^(2)2p^(6)3s^(2)3p^1$. Would you expect it to be easier to remove an electron from a $p$ orbital (with zero electron at the nucleus),...

1 Answers 1 views
Why is the first ionization energy of boron LESS than that of beryllium? Boron has a higher atomic number.

$Be, Z=4, 1s^(2)2s^2.$ $B, Z=5, 1s^(2)2s^(2)2p^1.$ A priori , should it be easier to remove a $p-$orbital electron, which by definition has zero electron at the nucleus? An $s-$orbital electron,...

1 Answers 1 views
Why does nitrogen have a higher ionization energy than oxygen?

Well, nitrogen atom has a first ionization energy of $"14.53 eV"$, so it would be $(b)$. But of course, you would not know that off-hand. To rationalize it, consider...

1 Answers 1 views
Why does oxygen have a lower ionization energy than oxygen?

Because nitrogen does not have any paired valence $2p$ electrons that can be removed, while oxygen does. Coulombic repulsion energy decreases the energy input required to remove a $2p$...

1 Answers 1 views
Why is the ionization energy of beryllium, $Z=4$, GREATER than the ionization energy of boron, $Z=5$?

And we consider the ELEMENT not the molecule, inasmuch as this is how ionization enthalpies are defined...... $"Atom(g)"+Deltararr"Atom(g)"^+ + e^(-)$ For $Be$ we gots $Z=4$, $1s^(2)2s^(2)$ For $B$ we gots...

1 Answers 1 views
Compare and contrast the **first** ionization energies of K and Ca? Compare and contrast the **second** ionization energies of K and Ca?

There are three factors which decide how easily an electron can be removed, in this order of priority: Number of shells (distance from the nucleus in effect) Effect...

1 Answers 1 views
X