Fundamental concepts of chem ch 4

Write the name for each covalent compound. SiF4 NO2 CS2 P2O5

silicon tetrafluoride nitrogen dioxide carbon disulfide diphosphorus pentoxide

Some molecules contain ___ ___ , covalent bonds in which three pairs of electrons are shared by two atoms.

triple bonds

The shape of a molecule is determined by the fact that covalent bonds, which are composed of negatively charged electrons, tend to repel one another. This concept is called the ___ ___ ___ ___ ___ ___ theory.

valence shell electron pair repulsion (VSEPR)

___ are hydrocarbons with a carbon-carbon triple bond (denoted C≡C) as part of their carbon skeleton.

Alkynes

Write the molecular formula for each compound. chlorine trifluoride phosphorus pentachloride sulfur dioxide dinitrogen pentoxide

ClF3 PCl5 SO2 N2O5 (The di- prefix on nitrogen indicates that two nitrogen atoms are present.)

Write two covalent compounds that have common rather than systematic names.

H2O and NH3 (water and ammonia) (answers will vary)

Write the formula for each covalent compound. iodine trichloride disulfur dibromide arsenic trioxide xenon hexafluoride

ICl3 S2Br2 AsO3 XeF6

___ ___ is the study of the chemistry of carbon compounds.

Organic chemistry

Which is the correct molecular formula—H4Si or SiH4? Explain

SiH4; except for water, hydrogen is almost never listed first in a covalent compound.

If an OH group (also called a hydroxyl group) is substituted for a hydrogen atom in a hydrocarbon molecule, the compound is an ____.

alcohol

These hydrocarbons are called ___ ___ ___

alkanes (saturated hydrocarbons).

Some hydrocarbons have one or more carbon-carbon double bonds (denoted C=C). These hydrocarbons are called

alkenes

The bond in a hydrogen molecule, measured as the distance between the two nuclei, is about 7.4 × 10−11 m, or 74 picometers (pm; 1 pm = 1 × 10−12 m). This particular ___ ___ represents a balance between several forces: the attractions between oppositely charged electrons and nuclei, the repulsion between two negatively charged electrons, and the repulsion between two positively charged nuclei

bond length

Identify whether each compound has ionic bonds, covalent bonds, or both. Na3PO4 K2O COCl2 CoCl2

both ionic covalent ionic

Write the name for each compound. BrF5 S2F2 CO

bromine pentafluoride disulfur difluoride carbon monoxide

Another important family of organic compounds has a ___ ___, in which a carbon atom is double-bonded to an oxygen atom and to an OH group.

carboxyl group

Compounds with a carboxyl functional group are called ___ ___, and their names end in -oic acid.

carboxylic acids

The sharing of electrons between atoms is called a ___ ___, and the two electrons that join atoms in a covalent bond are called a ___ ___ ___ ___.

covalent bond,bonding pair of electrons.

There are now eight electrons around each atom. Two pairs of electrons shared between two atoms make a ____ ____ between the atoms, which is represented by a double dash

double bond

To judge the relative polarity of a covalent bond, chemists use ___ which is a relative measure of how strongly an atom attracts electrons when it forms a covalent bond.

electronegativity

The carbon-carbon double and triple bonds are examples of ___ ___ in organic chemistry.

functional groups

The simplest organic compounds are the ___ , compounds composed of carbon and hydrogen atoms only.

hydrocarbons

The chemical formulas for covalent compounds are referred to as___ ___ because these compounds exist as separate, discrete molecules.

molecular formulas

The mass of a molecule—the ___ ___ (sometimes called the molecular weight)—is simply the sum of the masses of its atoms.

molecular mass

A discrete group of atoms connected by covalent bonds is called

molecule

Identify whether each compound has covalent bonds. NaI Na2CO3 N2O SiO2

no yes yes yes

Each fluorine atom has six electrons, or three pairs of electrons, that are not participating in the covalent bond. Rather than being shared, they are considered to belong to a single atom. These are called ___ ___ ___ ___ ___ of electrons.

nonbonding pairs (or lone pairs)

A covalent bond that has an equal sharing of electrons is called a

nonpolar covalent bond.

A covalent bond that has an unequal sharing of electrons is called a

polar covalent bond.