Chemistry Reference
In-Depth Information
3.
[non-polar covalent]—Hydrogen has an electronegativity of 2.2, and
hydrogen has an electronegativity of 2.2 (2.2 - 2.2 = 0.0), giving us an E.N.
difference of 0.0.
4.
[ionic]—Barium has an electronegativity of 0.9, and iodine has an
electronegativity of 2.7 (2.7 - 0.9 = 1.8), giving us an E.N. difference of 1.8.
5.
[polar covalent]—Carbon has an electronegativity of 2.6, and oxygen has an
electronegativity of 3.5 (3.5 - 2.6 = 0.9), giving us an E.N. difference of 0.9.
6.
[polar covalent]—Nitrogen has an electronegativity of 3.1, and oxygen has an
electronegativity of 3.5 (3.5 - 3.1 = 0.4), giving us an E.N. difference of 0.4.
Lesson 4-2 Review
1.
[ionic]
2.
[molecular]
3.
[intermolecular]
4.
[polyatomic]—The atoms of a polyatomic ion are held together by covalent
bonds, but the entire substance becomes a charged ion.
5.
[B. Al(OH)
3
]—Neutral compounds that contain polyatomic ions have both
ionic and covalent bonds. Covalent bonds hold the polyatomic ion together,
and then ionic bonds hold the polyatomic ion to other ions. The hydroxide
ion (OH
-
) is the only polyatomic ion that appears in our answer choices, so
answer B must be correct.
Lesson 4-3 Review
1.
[B.]—The notation for argon shows a complete octet (eight electrons),
which represents a stable element. The barium ion also shows a complete
octet, but the question asked for a neutral element.
2.
[A.]—The charge of +2 that appears with the diagram for the barium ion
indicates that it has lost two electrons.
3.
[C.]—Bromine has seven valence electrons. Forming a single covalent bond
will complete its octet.
4.
[D.]—Lithium is an alkali metal with one valence electron. Losing its one
valence electron will expose its inner energy level, giving it the configuration
of helium.
5.
[C.]—Answer C represents the compound ethyne, which has a molecular
formula of C
2
H
2
. The three pairs of dots found between the carbon atoms
represent a triple covalent bond.
6.
[A.]—Each pair of electrons found between two atoms represents a
covalent bond. Answer A shows the dot diagram for the compound butane,
which has thirteen pairs of shared electrons.
