Question 1

The source of an atom's electronegativity is the

Accepted Answer

A) repulsive force occurring among electrons within the same shell. 
B) repulsive force occurring between electrons within neighboring shells. 
C) positively charged atomic nucleus. 
D) kinetic energy electrons have orbiting the nucleus.

Question 2

Which of the following is an ion?

Accepted Answer

A) 2 H2 
B) Br2 
C) HCl 
D) Au + 3 Br2 
E) none of the above

Question 3

The separation of charges within a polar molecule is called a(n)

Accepted Answer

A) dipole. 
B) dipole-dipole. 
C) ionic bond. 
D) strong attraction. 
E) polar bond.

Question 4

The concept of a chemical bond is

Accepted Answer

A) how two or more atoms are held together. 
B) the sharing of nucleons. 
C) how two or more electrons reside in an orbital. 
D) how much energy it takes to remove an electron from a set of atoms. 
E) none of the above

Question 5

Which are closer together: the two nuclei within potassium fluoride,KF,or the two nuclei within molecular fluorine, F2 ?

Accepted Answer

A) KF 
B)  F2 
C) Both are the same.Any atom bonded to F will have the same inter-nuclear separation. 
D) It makes little sense to compare two molecules which exist in different physical states.KF is a solid while F2

Question 6

Which of the above substances would have the lowest boiling point?

Accepted Answer

A) a 
B) b 
C) c 
D) All boil at the same temperature. 
E) All are gases.

Question 7

Given the following diagram,describe what happens electronically between these two molecules.

Accepted Answer

A) Oxygen B becomes slightly positively charged due to the electrons on the water molecule. 
B) Oxygen A becomes slightly positively charged due to the electrons on the water molecule. 
C) Oxygen W becomes slightly negatively charged due to the oxygen molecule. 
D) Oxygen W becomes slightly positively charged due to the oxygen molecule. 
E) none of the above

Question 8

How is it possible for a neutral molecule,such as water,to form an ion?

Accepted Answer

A) It can combine with a hydrogen ion to form a positively charged species. 
B) It can combine with a chloride ion to form a negatively charged species. 
C) It can fragment into protons and electrons. 
D) It can absorb electrons and become negatively charged. 
E) It can absorb electrons and become positively charged.

Question 9

Given that the total number of atoms on our planet remains fairly constant,how is it ever possible to deplete a natural resource such as a metal?

Accepted Answer

A) The problem remains that not everyone recycles as they should. 
B) Recycling only forestalls the inevitable depletion of metal resources. 
C) The atoms don't leave our planet,which is why naturally occurring materials never really reach the point of depletion. 
D) The problem is with the expense of collecting metal atoms that are uniformly dispersed.

Question 10

Plastic wrap is made of nonpolar molecules and is able to stick well to polar surfaces,such as glass,by way of dipole/induced dipole molecular attractions.How is it that plastic wrap also sticks to itself so well?

Accepted Answer

A) by way of dipole-dipole molecular attractions 
B) by way of dipole-induced dipole molecular attractions 
C) Ions are formed as the plastic rubs against itself. 
D) by way of induced dipole-induced dipole molecular attractions

Question 11

Magnesium ions carry a 2+ charge,and chloride ions carry a 1- charge.What is the chemical formula for the ionic compound magnesium chloride?

Accepted Answer

A) MgCl 
B)  Mg2Cl 
C) Mg Cl2 
D)  Mg2 Cl2

Question 12

Barium ions carry a 2+ charge,and nitrogen ions carry a 3- charge.What would be the chemical formula for the ionic compound barium nitride?

Accepted Answer

A)  Ba3 N2 
B)  Ba2 N3 
C)  Ba3 N4 
D)  Ba2 N2

Question 13

Why does an atom with many valence electrons tend to gain electrons rather than lose any?

Accepted Answer

A) Atoms with many valence electrons tend to have relatively weak forces of attraction between the valence electrons and the nucleus.Therefore,the outer electrons are free to attract other electrons. 
B) There is stability in numbers.Atoms with many valence electrons are always attracting new electrons. 
C) The old adage that "he who has,gets" is also true in atomic structure.Atoms with many valence electrons can essentially overpower atoms with few valence electrons and attract additional electrons. 
D) Atoms with many valence electrons tend to have relatively strong forces of attraction between the valence electrons and the nucleus.This makes it easy for them to gain additional electrons.

Question 14

Which of the following would have the highest boiling point?

Accepted Answer

A) C6H14 
B) C8H18 
C) C10H22 
D) C12H26 
E) not enough information given

Question 15

A substance consisting of which molecule shown below should have a higher boiling point?

Accepted Answer

A) The molecule on the left,COCl2 ,because it has a fewer number of atoms. 
B) The molecule on the right, C2  H2   Cl,because it has a greater number of atoms. 
C) The molecule on the left,CO Cl2  ,because it is less symmetrical. 
D) The molecule on the right, C2  H2

Question 16

Which of the following molecules is the most polar?

Accepted Answer

A) HCl 
B) BrF 
C) CO 
D)  Br2

Question 17

How many covalent bonds would the following atom usually form?

Accepted Answer

A) 1 
B) 2 
C) 4 
D) 6 
E) It would tend to form ionic bonds.

Question 18

Distinguish between a metal and a metal-containing compound.

Accepted Answer

A) There is no distinction between the two. 
B) Only one of these contains ionic bonds. 
C) Only one of these contains covalent bonds. 
D) Only one of these occurs naturally.

Question 19

Consider the boiling points of the following compounds and their solubilities in room-temperature water.Why does the solubilities in water go down as the boiling points of these alcohols go up. $\quad $$\quad $$\quad $$\quad $$\quad $$\quad $ $\quad $$\quad $ 
$\begin{array}{llcc}\text { Boiling point: } & 65^{\circ} \mathrm{C} &\quad \quad \quad  117^{\circ} \mathrm{C} &\quad \quad \quad \quad \quad \quad  138^{\circ} \mathrm{C} \
\text { Solubility: } & \text { infinite } & \quad \quad \quad 8 g / 100 \mathrm{~mL} & \quad \quad \quad \quad 2.3g/ 100 \mathrm{~mL}
\end{array}$

Accepted Answer

A) Larger molecules are less attracted to one another by induced dipole-induced dipole as well as by dipole-dipole and dipole-induced dipole attractions. 
B) As the boiling increases,it is more difficult to keep the alcohol from evaporating out of solution. 
C) As the boiling point increases,the size of the alcohol molecules decreases. 
D) Larger molecules are more attracted to one another by induced dipole-induced dipole as well as by dipole-dipole and dipole-induced dipole attractions.

Question 20

In terms of the periodic table,is there an abrupt or gradual change between ionic and covalent bonds?

Accepted Answer

A) There is an abrupt change that occurs across the metalloids. 
B) Actually,any element of the periodic table can form a covalent bond. 
C) There is a gradual change: the farther apart,the more ionic. 
D) Whether an element forms one or the other depends on nuclear charge and not the relative positions in the periodic table.

Exam 15: How Atoms Bond and Molecules Attract