Video Transcript
Fill in the blank. Electronegativity can be described
as blank. (A) How much negative charge is
generated by the electrons orbiting the nucleus of an atom. (B) How much polarity is focused on
the central atom of a covalent molecule. (C) How strongly an atom attracts
the electrons from a chemical bond. (D) How strongly an atom forms a
hydrogen bond with a nearby water molecule. Or (E) how strongly the nucleus
attracts the outer electrons of an atom toward the center.
For this question, we must identify
the description of the term “electronegativity.” Let’s clear some space on screen to
investigate this term.
In order to discuss
electronegativity, we must understand covalent bonds. A covalent bond forms when two
nonmetal atoms share one or more pairs of electrons. The shared electrons form the
chemical bond between the two atoms. The atoms engaging in covalent
bonds are often not the same element. We can use water as an example to
look at covalent bonds between different elements. Its chemical formula is H2O. Water molecules have two hydrogen
atoms and one oxygen atom in each molecule. In the water molecule, each
hydrogen atom forms a covalent bond with the oxygen atom.
Each element on the periodic table
has its own physical and chemical properties. One of these very important
properties is called electronegativity. Electronegativity is the measure of
how strongly an atom attracts a pair of electrons from a chemical bond. Oxygen is considered to have a high
electronegativity. Hydrogen is less electronegative
than oxygen.
Electronegativity varies among the
elements of the periodic table. In the water molecule, oxygen is
the more electronegative atom. So it attracts the bonding
electrons more strongly. The electrons are still shared in
the covalent bonds, but they are shared unevenly. This causes the side of the
molecule with oxygen pulling the electrons more strongly to be partially
negative. This is represented using a 𝛿
minus symbol. This causes the side of the
molecule with hydrogen atoms to be partially positive. This is represented using 𝛿 plus
symbols. In the water molecule, we can see
how electronegativity is an important property of the atoms and how it affects the
chemical bonds.
Let’s have another look at our
answer choices. We can see that answer choice (C)
describes electronegativity. So we can now fill in the
blank. Electronegativity can be described
as how strongly an atom attracts the electrons from a chemical bond.
