3.4 An Atomic-Level View of Elements and Compounds Flashcards
Recall from Chapter 1 that we can categorize pure substances as either ______ or ______ .
Recall from Chapter 1 that we can categorize pure substances as either elements or compounds.
We can subcategorize elements and compounds according to the basic ____ that compose them.
We can subcategorize elements and compounds according to the basic units that compose them.
Elements may be either _____ or _____ .
Elements may be either atomic or molecular.
Compounds may be either _______ or _______.
Compounds may be either molecular or ionic.
Atomic elements exist in nature with single _______ as their basic units.
Atomic elements exist in nature with single atoms as their basic units.
helium is composed of _____ atoms.
helium is composed of helium atoms.
_______ _______ do not normally exist in nature with single atoms as their basic units; instead, they exist as molecules—two or more atoms of the element bonded together.
Molecular elements do not normally exist in nature with single atoms as their basic units; instead, they exist as molecules—two or more atoms of the element bonded together.
Most molecular elements exist as ________ molecules.
Most molecular elements exist as diatomic molecules.
ydrogen is composed of __ molecules, nitrogen is composed of __ molecules, and chlorine is composed of __ molecules.
ydrogen is composed of H2 molecules, nitrogen is composed of N2 molecules, and chlorine is composed of Cl2 molecules.
A few molecular elements exist as _______ molecules
A few molecular elements exist as polyatomic molecules
Phosphorus exists as__, and sulfur exists as __. Figure 3.5 ▼ shows the elements that exist primarily as diatomic or polyatomic molecules.
Phosphorus exists as P4, and sulfur exists as S8. Figure 3.5 ▼ shows the elements that exist primarily as diatomic or polyatomic molecules.
Propane is an example of a _____ compound
Propane is an example of a molecular compound
The basic units that compose propane gas are propane (____) molecules.
The basic units that compose propane gas are propane (C3H8) molecules.
Table salt (NaCl) is an ____ compound.
Table salt (NaCl) is an ionic compound.
Table salt formula unit is the simplest charge-neutral collection of ions: one Na+ ion and one Cl- ion.
Table salt formula unit is the simplest charge-neutral collection of ions: one Na+ ion and one Cl- ion.
______ ______ are usually composed of two or more covalently bonded nonmetals.
Molecular compounds are usually composed of two or more covalently bonded nonmetals.
The basic units of molecular compounds are molecules composed of the ________ atoms.
The basic units of molecular compounds are molecules composed of the constituent atoms.
water is composed of ___ molecules
water is composed of H2O molecules
dry ice is composed of ___ molecules
dry ice is composed of CO2 molecules
propane (often used as a fuel for grills) is composed of ____ molecules
propane (often used as a fuel for grills) is composed of C3H8 molecules
________ ________ are composed of cations (usually a metal) and anions (usually one or more nonmetals) bound together by ionic bonds.
Ionic compounds are composed of cations (usually a metal) and anions (usually one or more nonmetals) bound together by ionic bonds
The basic unit of an ionic compound is the _____ ___, the smallest, electrically neutral collection of ions.
The basic unit of an ionic compound is the formula unit , the smallest, electrically neutral collection of ions.
A formula unit is not a _____ —it does not usually exist as a _____ entity but rather as part of a larger _____ .
A formula unit is not a molecule—it does not usually exist as a discrete entity but rather as part of a larger lattice.
the ionic compound table salt, with the formula unit NaCl, is composed of Na+ and Cl- ions in a ___-to-___ ratio
the ionic compound table salt, with the formula unit NaCl, is composed of Na+ and cl- ions in a one-to-one ratio
Table salt, Na+ and Cl- ions exist in a _____-dimensional alternating _____
able salt, Na+ and Cl- ions exist in a three-dimensional alternating array
ionic bonds are not _______, no one Na+ ion pairs with a specific Cl- ion
ionic bonds are not directional, no one Na+ ion pairs with a specific Cl- ion
Many common ionic compounds contain ions that are themselves composed of a group of _______ bonded atoms with an overall _______.
Many common ionic compounds contain ions that are themselves composed of a group of covalently bonded atoms with an overall charge.
Hypochlorite is a _______ ion— an ion composed of two or more atoms—with the formula ClO-.
Hypochlorite is a polyatomic ion— an ion composed of two or more atoms—with the formula ClO-.
Classify the substances as an atomic element, molecular element, molecular compound, or ionic compound.
xenon
Xenon is an element. It is not a molecular element (see Figure 3.5 ); therefore, it is an atomic element.
Classify the substances as an atomic element, molecular element, molecular compound, or ionic compound.
NaNO3
NaNO3 is a compound composed of a metal and a polyatomic ion; therefore, it is an ionic compound
Classify the substances as an atomic element, molecular element, molecular compound, or ionic compound.
NiCl2
NiCl2 is a compound composed of a metal (left side of the periodic table) andnonmetal (right side of the periodic table); therefore, it is an ionic compound.
Classify the substances as an atomic element, molecular element, molecular compound, or ionic compound.
bromine
Bromine is one of the elements that exists as a diatomic molecule (see Figure 3.5 ); therefore, it is a molecular element.
Classify the substances as an atomic element, molecular element, molecular compound, or ionic compound.
NO2
NO2 is a compound composed of a nonmetal and a nonmetal; therefore, it is a molecular compound
