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Name: Ashley
Status: student
Grade: 9-12
Location: TX
Country: USA
Date: Fall 2009


Question:
What is the relationship between ionization energy and electronegativity, are they inversely related, or unrelated?



Replies:
Ashley,

There are some general trend relationships between ionization energy and electronegativity. In general, since the first ionization energy tends to increase as you go left to right along a period (row), and electronegativity does the same - we say that they follow the same trend. Similarly as you go from top to bottom of a group (column), both first ionization energy and electronegativity decreases, again we say that they follow the same trend.

However, we do have to be a bit careful with this. This is a *trend*. This means that there are some variations, a few exceptions that do not fit the trend. In general though, we can say that they are directly related.

Another important point is that, ionization energy is an actual set of data that is determined experimentally. Electronegativity is a derived information based on many different data only one of which is ionization energy.

Greg (Roberto Gregorius)
Canisius College


Ashley,

These two characteristics of an element are related, but not absolutely.

The first ionization energy is the energy required to remove one electron from a gaseous neutral atom (it is usually given as a value per mole of atoms). The more strongly the outer electron that would be removed in ionization is attracted to the nucleus, the more energy is required. The more repulsion from other electrons in the atom, the less energy is required.

Electronegativity is the ability for the atom to attract electrons in a chemical bond. It is measured on the Pauling scale where F = 4.0 (the most electronegative).

I'm sure that you can see that these two are related. If it takes more energy to remove an electron from an atom then the nucleus of that atom has a strong attraction to the outer electrons and will therefore have a strong attraction to electrons in any bond the atom is involved with, so the atom will also be electronegative.

The relationship is fairly clear and you could show this by plotting electronegativity vs 1st ionization energy for all the elements you can find data on.

Best wishes,

Tom Collins


Ashley

From:
http://en.wikipedia.org/wiki/Ionization_energy

The term ionization energy (EI) (of an atom or molecule) is most commonly used to refer to the energy required to remove (to infinity) the outermost electron in the atom or molecule when the gas atom or molecule is isolated in free space and is in its ground electronic state. This quantity was formerly called ionization potential, and was at one stage measured in volts.

And from:
http://en.wikipedia.org/wiki/Electronegativity

Electronegativity, symbol รท, is a chemical property that describes the ability of an atom (or, more rarely, a functional group) to attract electrons (or electron density) towards itself in a covalent bond.[1] An atom's electronegativity is affected by both its atomic weight and the distance that its valence electrons reside from the charged nucleus. The higher the associated electronegativity number, the more an element or compound attracts electrons towards it.

So it does not look like either are dependent (related to) on the other.

Sincere regards,

Mike Stewart



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