# How can we know that which element is more electronegative than other ? I've never come across any such formula or trick for this,except learning it by practice. Please tell if you know any.

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Eg: in heterolytic fission of CO, we know that oxygen will take both the electrons but what if there was some other element whose relative electronegativity I dont know, then how can I solve it.

Eg: in heterolytic fission of CO, we know that oxygen will take both the electrons but what if there was some other element whose relative electronegativity I dont know, then how can I solve it.

##### 2 Answers

#### Answer:

Electronegativity INCREASES across a Period, from left to right as we face the Table...........

#### Explanation:

And excluding the

Why should this be so? Electronegativity tends to be a function of NUCLEAR charge (and thus dependent on

Down a Group, the

And so let's have a gander at the Pauling Scale, and examine the electronegativities:

Is this representation roughly consistent with what I have argued? The most electronegative element should thus be fluorine, and indeed it is. On the other hand, the LEAST electronegative elements should be the alkali, and alkaline-earth metals. Is this true?

This is one of the most important trends a chemistry undergraduate can learn. If you are unsatisfied with this answer, or seek clarification, voice your objection, and someone will address the issue.

And thus in your example, for

#### Answer:

Actually there are 4 or 5 formulae for calculating electronegativity according to different models.....

#### Explanation:

Pauling, Allen, Mullikan, Sanderson and Allred-Rochow all came up with models from which electronegativity values can be derived using formulae. None of them are especially "simple" calculations, and you will need a decent chemical data book to hand to find the various values to plug in. However, it's certainly do-able.

Wikipedia actually lists the various methods and explains how to do them here en.wikipedia.org/wiki/Electronegativity#Methods_of_calculation