ch 5 pt

Which formula is least likely to represent a molecular compound that really exists? A. Br3Cl5 B. PCl5 C. SF6 D. C2H6 E. SF4

A. Br3Cl5

The element in the list given that is most likely to form a coordinate covalent bond is A. Fe B. Ca C. H D. C E. K

A. Fe

The covalent bonding model is most useful in describing which of the following compounds? A. SCl2 B.CoCl2 C. NiCl2 D. MgCl2 E. none of the above

A. SCl2

the element least likely to obey the octet rule in forming chemical bonds is A. boron B. fluorine C. nitrogen D. carbon E. oxygen

A. boron

a chemical bond formed when two atoms share four electrons is a ______ bond; it is best described as ________. A. double; covalent B. single; covalent C. single; ionic D. double; ionic E. triple, covalent

A. double; covalent

Which property could describe a covalent compound? A. it is a gas at room temperature B. it conducts electricity when melted C. it conducts electricity when dissolved in water D. it is composed of a non-metal and a metal E. none of the above.

A. it is a gas at room temperature

A molecule in which the central atom forms three single bonds and has one lone pair is said to have a _____ shape. A. pyramidal B. bent C. linear D. planar E. tetrahedral

A. pyramidal

The VSEPR model or molecular structure requires knowledge of _____ to predict the geometry of an atom in a molecule. A. the number of atoms bonded to the atom of interest B. the number of electron pairs on the atoms of interest C. the total number of atoms in the molecule D. both A and C E. none of the above

A. the number of atoms bonded to the atom of interest

The common nomenclature of ions, our and ic are used as endings for the ions. In this system which species is named with the ous ending? A. the species with the lower positive charge B. the species with the higher negative charge C. It varies from species to species D. the species with the lower negative charge E. the species with the higher positive charge

A. the species with the lower positive charge

A molecule that contains three identical polar bonds to the central atom will be. A. non polar in all cases B non polar if the geometry is planar triangular C. either polar of non polar depending on the identity of the atoms bonded to the central atom D. polar in all cases E. impossible to tell the polarity

B non polar if the geometry is planar triangular

Which representation of a hydrogen molecule is not correct A. H:H B. H=H C. H2 D. H-H E. none of the above

B. H=H

The water molecule has a ___ geometry because its central atom has _____ bonds and _____ lone pairs A. linear; two; two B. bent; two; two C. tetrahedral; four; zero D. pyramidal; three; one E. planar triangular, three; one

B. bent; two; two

which element listed is the most electronegative? A. aluminum B. chlorine C. sodium D. iodine E. bromine

B. chlorine

The bond angle in the molecule H2S is ______ because the _____ A. exactly 180 degrees; the S atom has two bonds B. less than 109.5 degrees; lone pairs force the hydrogen atoms closer together. C. exactly 109.5; the S atom has four charge clouds D. greater than 109.5 degrees; lone pairs allow the bond angle to expand. E. exactly 120 degrees; lone pairs are counted as one charge cloud.

B. less than 109.5 degrees; lone pairs force the hydrogen atoms closer together.

The element lest likely to obey the octet rule in forming chemical bonds is A. fluorine. B. neon C. nitrogen D. carbon E. oxygen

B. neon

The molecule SiCl4 has a _____ shape A. linear B. tetrahedral C. bent D. pyramidal E. planar

B. tetrahedral

a molecule in which the central atoms has no lone pairs and forms four single bonds is said to have a _____ shape. A. bent B. tetrahedral C. linear D. planar E. pyramidal

B. tetrahedral

a chemical bond formed when two atoms share six electrons is a _______ bond; it is best described as _______. A. single; covalent B. triple; covalent C. single; ionic D. double; ionic E. double; covalent

B. triple; covalent

Bromine pentafluoride

BrF5

The number of valence electrons in the acetic acid molecule (CH3CO2H) is _____ A. 16 B. 8 C. 24 D. 0 E. 32

C. 24

The formula for carbon disulfide is A. CSi2 B. C2s C. CS2 D. CaS2 E. (CS)2

C. CS2

which of the following molecules has a CCH bond angle of 180 degrees? A. H3CCH3 B H3CCHo C. HCCH D. H2CCH2 E. none of them

C. HCCH

which element is most. likely to form three covalent bonds? A. Se B. Si C. P D. S E. C

C. P

The carbon dioxide molecule is linear. The electronegativities of C and O are 2.5 and 3.5 respectively. Based on these values and on consideration of molecular geometry, the C-O bond is ______ and the molecule is ______. A. non-polar; non-polar B. non-polar; polar C. Polar; non-polar D. polar; polar E. none of the above

C. Polar; non-polar

If SiCl4 is named as a covalent compound, what would it be called? A. chlorosilicate B. Sulfur tetrachloride C. Silicon tetrachloride D. silicon chloride E. sulfur chloride

C. Silicon tetrachloride

according to VSEPR theory, a molecule with three charge clouds including one lone pair would have a _______ shape. A. planar trianglular B. tetrahedral C. bent D. pyramidal E. linear

C. bent

Elements in period 3 below down always "obey" the octet rule because they A. can only use p orbitals for bonding B. cannot use s or vitals for bonding C. can use s, p and d orbitals for bonding D.can use s and p orbitals for bonding E. cannot use d orbitals for bonding

C. can use s, p and d orbitals for bonding

Which element listed is the least electronegative? A. oxygen B. fluorine C. hydrogen D. nitrogen E. chlorine

C. hydrogen

Which physical property is most closely associated with covalent molecules? A. it is composed of a metal and a nonmetal B. it has a very high melting point C. it is a gas at room temperature D. it conducts electricity when dissolved in water. E. none of these

C. it is a gas at room temperature

The smallest possible unit of a covalent compound is a(n) A. Formula unit B. cation C. molecule D. atom E. polyatomic ion

C. molecule

consider a bent molecule, such as H2Se, in which the central atom has two lone pairs of electrons. The electronegativities of H and Se are 2.1 and 2.4, respectively. Based on these values and on consideration of molecular geometry, the H-Se bond can be considered almost _________ and the molecule is ______. A. polar; non-polar B non-polar; non-polar C. non-polar; polar D. polar; polar E. none of the above

C. non-polar; polar

in forming covalent bonds where the octet rule is obeyed sulfur usually forms _____ bonds and chlorine usually forms _____ bonds A. six; seven B. one; two C. two; one D. two; two E. one; one

C. two; one

carbon tetrachloride

CCl4

methane

CH4

carbon monoxide

Co

The formula for sulfur hexabromide is A. SF6 B. SBr4 C. SiBr6 D. SBr6 E. SiB6

D. SBr6

in a covalent compound the bond length can be defined as A. the distance between two nuclei when the attraction is greater. B. the distance between two nuclei when the repulsion is greatest. C. the distance between the two large atoms D. The distance between two nuclei when repulsion and attraction are balanced. E. the distance between any two pairs of electrons.

D. The distance between two nuclei when repulsion and attraction are balanced.

If the elements W, X, Y and Z have electronegativity values of 1.0, 2.0, 2.5, and 3.5, respectively, which bond is the least polar? A. WZ B. XZ C. YZ D. XY E. WX

D. XY

A chemical bond formed when two atoms share two pairs of electrons is a _____ bond; it is best described as _______. A. single; ionic B. double; ionic C. single; covalent D. double; covalent E. triple; covalent

D. double; covalent

Which group contains only elements which normally exist as diatomic molecules? A. hydrogen, lithium, sodium B. oxygen, phosphorus, germanium C. helium, neon, argon D. nitrogen, oxygen, fluorine E. nitrogen, sulfur, bromine

D. nitrogen, oxygen, fluorine

A molecule in which the central atom forms one double bond and two single bonds is said to have a ____ shape. A. tetrahedral B. bent C. pyramidal D. planar triangular E. linear

D. planar triangular

Consider the molecule SiCl4. The electronegativity values for Is and Cl are 1.8 and 3.0, respectively. Based on these values and on consideration of molecular geometry, the Si-Cl bond is _____ and the molecule is _____ A. non-polar; polar B. non-polar; non-polar C. polar; polar D. polar; non-polar E. non of the above

D. polar; non-polar

a chemical bond formed when two atoms share three pairs of electrons is a _____ bond; it is best described as _______. A. double; ionic B. Single; covalent C. double; covalent D. triple; covalent E. Triple; ionic

D. triple; covalent

Which set of properties would identify a unknown while solid as a molecular compound? I. contains a metal II. has a definite crystal structure III. dissolves in water, but not in organic liquids IV. melts at 80 degrees celsius V. does not conduct electricity when melted A. I, III, V B I, IV, V C. II, III, IV D. I, II, III E. II, IV, V

E. II, IV, V

In a lewis dot structure the electrons which complete an octet but are not located between two atoms are referred to as A. delta minus electrons B. excess electrons C. filled shells D. bonding pairs E. lone pairs

E. Lone pairs

a chemical bond formed when two atoms share two electrons is a _____ bond; it is best described as _____. A. single; ionic B. tiple; covalent C. double; covalent D. double; ionic E. single; covalent

E. Single; covalent

The compound BrF3 would be called A. tri (bromine fluoride) B. boron trifluoride C. tribromine fluoride D. triboron fluoride E. bromine trifluoride

E. bromine trifluoride

A chemical bond formed when two atoms share one pair of electrons is a ____ bond; it is best described as _____ A. double; covalent B. double; ionic C. single, ionic D. Triple; covalent E. single; covalent

E. single; covalent

the element least likely to obey the octet rule in forming chemical bonds is A. fluorine B. nitrogen C. calcium D. sodium E. sulfur

E. sulfur

A chemical bond formed between two identical atoms is a(n) ______ bond A) Molecular B) hydrogen C) atomic D) ionic E) covalent

E. wcovalent

iodine monochloride

ICl

iodine heptafluoride

IF7

dinitrogen tetroxide

N2O4

ammonia

NH3

oxygen difluoride

OF2

phosphorus trichloride

PCl3

The formula for phosphorus pentafluoride is ____ A. PF5 B. P5F5 C. P5F D. (PF)5 E PhF5

PF5

sulfur hexafluoride

SF6

when a non-metal atom bonds with another non-metal atom, an ionic bond is formed.

false

What is the systematic name of ICl3? A. iodine Trichloride B. iodine chloride C. Iodine (III) chloride D. triiodine chloride E. Tri(iodine chloride

iodine Trichloride

Covalent compounds form distinct molecules, and therefore may exist as gases, liquids, or solids at room temperature, depending on the characteristics of the compounds. true or false

true

When two atoms share one or more pairs of electrons, a covalent bond is formed.

true

Although noble gases do not normally form covalent compounds, XeO3 has been prepared. The systemic name of this compound is A. trioxy xenon B xenon trioxide C. triexenon trioxide D. xenon (III) oxide E. none of the above

xenon trioxide