Chapter 6 review
Covalent Bond
2 nonmetals
How is an electron dot diagram a useful model for focusing on the chemical properties of an element?
An electron dot diagram shows the number of valence electrons. The chemical properties of an element depend on the number of valence electrons in its atoms.
Beryllium, Be, and chlorine, Cl, form a binary ionic compound with a one-to-two ratio of beryllium ions to chloride ions. The formula for the compound is
BeCl2
In potassium bromide, KBr, which element forms anions?
Bromine
The chemical formula for calcium chloride, CaCl2, shows that the compound contains two ???? ions for every ????? ion.
Chloride, Calcium
Sodium, an alkali metal, and chlorine, a halogen, are both in Period 3 of the periodic table. Which element has a higher ionization energy? Explain your answer.
Chlorine, it gains electrons
Are covalent bonds more likely to be found in compounds containing both metals and nonmetals or compounds containing only nonmetals?
Compounds containing only nonmetals.
You see a structural formula in which the symbols for elements are connected by a long dash. You can assume that the chemical bonds in the compound are
Covalent
In a periodic table that included electron dot diagrams, in which column would the diagrams contain more dots—Group 2A (the alkaline metals) or Group 6A (the oxygen family)?
Group 6A the oxygen family
In the binary ionic compound lithium iodide, LiI, which element forms anions?
Iodine
Study the electron dot diagrams in Figure 6-1. Which of the elements are most likely to react and form a compound? What type of compound are they likely to form?
L+C an Ionic compound because they are a metal and a nonmetal.
Which of the following compounds does NOT contain molecules?
NaCl
Study the electron dot diagrams for lithium, carbon, fluorine, and neon in Figure 6-1. Choose the statement that correctly identifies the most stable of the elements.
Neon is the most stable element because its highest occupied energy level is filled.
Which of the following formulas represents a compound whose molecules contain a triple bond?
N≡N
Suppose a covalent compound has a relatively high boiling point compared to molecules with a similar mass. Are the molecules in the compound likely to be polar or nonpolar?
Polar
In an electron dot diagram of potassium, there is one dot. In an electron dot diagram of silicon, there are four dots. Which element would you expect to be more reactive?
Potassium
In sodium chloride, NaCl, are the cations sodium ions or chloride ions?
Sodium chloride
The molecules in compound AB are strongly polar, while the molecules in compound XY are nonpolar. Which substance probably has the higher boiling point?
Substance AB's attractions are stronger
Fluorine is the most reactive nonmetal. To fluorine's immediate right in the periodic table is neon, a noble gas that does not form chemical bonds. Explain this contrast in reactivity in terms of atomic structure.
The electron configuration of an element determines its reactivity. Fluorine with seven valence electrons tends to gain one electron to fill its highest occupied energy level. Neon, with eight valence electrons has a stable electron configuration. Neon's highest occupied energy level holds the maximum possible number of electrons.
Ionic Bond
The share in electrons between a metal and a nonmetal
Typically, atoms gain or lose electrons to achieve
a stable electron configuration.
In an ionic compound, the attractions between cations and ????? hold the compound together.
anions
The ions in solid sodium chloride are arranged in a structure called a(an) ??????? lattice.
crystal
When two atoms of the same nonmetal react, they often form a(an)
diatomic molecule
27. If there are two long dashes between two atoms in a structural formula, molecules of the compound contain a(an) ????? bond.
double
A polar covalent bond forms when ????? are not shared equally between atoms.
electrons
In a polar covalent bond,
electrons are not shared equally between atoms.
When cesium and fluorine react, they form an ionic compound called cesium ??????.
flouride
Which of the following groups contain three elements with stable electron configurations?
helium, xenon, neon
You are given the melting points of three unknown substances and are asked to predict which one is an ionic compound. You would select the compound with the ?????? melting point.
highest
Ionization energies tend to
increase from left to right across a period.
The name iron(II) indicates that a compound contains
iron ions with a 2+ charge.
The water molecule H2O is polar because it contains two polar single bonds and
its molecule has a bent shape.
Fluorine, F, forms a binary ionic compound with lithium, Li. What is the name of this compound?
lithium fluoride
Water has a higher boiling point than expected because
of the strong attractions between polar water molecules.
KBr is the formula for an ionic compound. The fact that neither symbol is followed by a subscript means that there is a(an) ?????? ratio of ions in the compound.
one-to- one
A(An) ??????? ion is a covalently bonded group of atoms that has a positive or negative charge.
polyatomic
In the binary ionic compound potassium bromide, KBr, the element that forms cations is
potassium
Two factors that determine whether a molecule is polar are the types of atoms in the molecule and the ????? of the molecule.
shape
In an electron dot diagram, the symbol for an element is used to represent
the nucleus and all non- valence electrons
The formation of an ionic bond involves the
transfer of electrons
The elements most likely to form more than one type of ion are the
transition metals.
he compound whose formula is SO3 is called sulfur
trioxide
In the name carbon dioxide, the prefix of the second word indicates that a molecule of carbon dioxide contains
two oxygen atoms
In an electron dot diagram, each dot represents a(an)
valence electron
Because water molecules are polar and carbon dioxide molecules are nonpolar,
water has a higher boiling point than carbon dioxide does.
In ionic compounds, the sum of the charges of all the cations and anions must be
zero
