valance, valence

Valance or valance means a short curtain or drapery--
I think we should just put a valance at the top, without the long drapes.
Long sheer drapes with a dark blue valance would look nice.

Valence or valence means, in chemistry, the capacity of an atom to combine with other atoms, to form molecules or chemical compounds--
In water, oxygen has a valence of 2; the number is determined by the hydrogen atoms with which it can combine.
The valence of an element is a measure of its ability to combine with other atoms.

Valence is also a linguistic term, meaning the number of grammatical elements with which a word, particularly a verb, can combine--
What is the valence of the verb in the sentence "He went home" ?

Valence is also used by some psychologists to describe the negative or positive emotions associated with something--
Anger has a negative valence; joy has a positive valence.

Now that you know that, you can say--
"The scientist thought the curtains and the valance should combine as if by a valence bond."