Difference between Nuclear Charge and Effective Nuclear Charge – Chemistry

What is the nuclear charge in the periodic table?

The nuclear charge (Z) is defined as the total charge in the nucleus due to the presence of positive charge protons.

Nuclear Charge means Charge of Nucleus

As we move through the periodic table, the atomic number continuously increases due to the increase in the number of protons in the nucleus, thus the nuclear charge also increases.

Nuclear Charge Periodic Trend

Effective Nuclear Charge ( Zeff):

Effective Nuclear Charge is defined as” the net positive charge experienced by an electron in a poly electronic atom”.

Effective Nuclear Charge

The term “effective “is used due to the presence of negatively charged electrons in the inner shells prevents the nuclear effect to be fully experienced by the valence shell electrons( due to the shielding effect).

Effective Nuclear Charge Calculation:

In a poly electronic atom, the valence electrons are simultaneously attracted to the positively charged nucleus and repelled by the negatively charged electrons.

The effective nuclear charge calculated for such an electron is given by the following equation:

Zeff = Z- S

Where:

Z = total proton numbers in the nucleus of an atom

 (Atomic number)

S= shielding effect

Difference between Nuclear charge & Effective Nuclear charge:

Nuclear charge is the total electronic charge of the nucleus of an atom (due to the presence of the total number of protons in the nucleus) whereas effective nuclear charge is the attraction of the nucleus positive charge acting on the valence electrons.

Remember that the effective nuclear charge is always less than the total number of protons present in the nucleus due to the inner electron repulsion experienced by the valence electrons (shielding effect).

Effective Nuclear Charge Trend:

Effective nuclear charge increases across the period as the shielding effect remains constant.

Greater Effective Nuclear Charge = Greater attraction between nucleus and valence electrons = Small atomic size

Let’s take an example of period 3 elements to clearly understand the concept of effective nuclear charge.

As you can see in the table that when we move across the period from left to right, sodium (Na) has only one valence electron , Mg has 2 valence electrons , Al has 3 , Si has 4 , P has 5 , S has 6 ,Cl has 7 while argon(Ar) has eight valence electrons.

Moving across the period, the atomic number increases due to the increase of the number of protons in the nucleus. Therefore, nuclear charge of period 3 elements also increases.

Also on the addition of proton numbers in the nucleus, the electrons feel greater nuclear attraction because the inner shell electron number remains constant. Therefore, experience the same inner electron repulsion and increase nuclear attraction across the period.

Greater nuclear attraction on valence electrons pull the valence electrons closer to the nucleus and thus the atom gets smaller.

Down the group, the nuclear charge increase due to the increase in the proton numbers whereas the effective nuclear charge decreases due to the addition of electron shells the inner electron repulsion increases.

Which atom has greater nuclear charge and effective nuclear charge, sodium or chlorine?

As the sodium atom has 11 protons and the chlorine atom has 17 protons so due to the greater number of protons chlorine has a greater nuclear charge.

Also, an effective nuclear charge of chlorine is greater than sodium because both atoms having a same number of inner shell electrons experience the same inner electron repulsion.

Check out!!

-> Class 10 Chemistry Full book pdf

-> Class 11 Chemistry Full book pdf

-> Class 12 Chemistry Full book pdf

For joining best Chemistry Coaching


Recommended videos ( in Urdu / Hindi)

8 thoughts on “Difference between Nuclear Charge and Effective Nuclear Charge – Chemistry”

  1. First of all I would like to say excellent blog!
    I had a quick question in which I’d like to ask if you don’t mind.
    I was curious to know how you center yourself and clear
    your mind before writing. I have had a difficult time clearing my
    thoughts in getting my thoughts out. I truly do take pleasure in writing however it just seems like the first
    10 to 15 minutes are wasted just trying to figure
    out how to begin. Any suggestions or hints? Kudos!

  2. I’m extremely inspired with your writing abilities as neatly as with the format to your
    weblog. Is that this a paid subject or did you customize it your self?
    Either way stay up the excellent quality writing, it’s uncommon to look a nice
    weblog like this one these days..

  3. I’m not sure where you are getting your info, but great topic.
    I needs to spend some time learning more or understanding
    more. Thanks for magnificent info I was looking for this information for my mission.

  4. Attractive section of content. I just stumbled upon your blog and in accession capital to
    assert that I acquire actually enjoyed account your blog posts.
    Any way I will be subscribing to your feeds and even I achievement you access consistently fast.

  5. Hi there! I could have sworn I’ve visited this website before but
    after going through some of the articles I realized it’s new to
    me. Regardless, I’m certainly happy I stumbled upon it and I’ll be bookmarking it and checking back frequently!

    Also visit my page Moscatcher Review

  6. Thanks for the good writeup. It in reality was a amusement
    account it. Look complex to more brought agreeable from you!
    However, how could we keep up a correspondence?

Leave a Reply

%d bloggers like this: