CH 2 Supplemental Learning

Question 1

Orbitals are best described as __________.

Answer 1

a three-dimensional space where an electron spends most of its time with no more than 1 other electron, forming a pair

Question 2

Although all forms of life require _____, other elements are required only by certain species.

Answer 2

iron

Question 3

When a very electronegative atom strips a valence electron away from its partner, __________ form.

Answer 3

ions

Question 4

weak chemical bonds where there is an attraction between a hydrogen atom and an electronegative atom.

Answer 4

Hydrogen bonds

Question 5

weak chemical reaction that occurs only when atoms and molecules are very close together.

Answer 5

“Van der Waals interactions

Question 6

the sharing of a pair of valence electrons by two atoms.

Answer 6

Covalent bonds

Question 7

the sharing of a pair of valence electrons by two atoms, where one of the atoms is strongly electronegative.

Answer 7

Polar covalent bonds

Question 8

Because of their opposite charges, cations and anions attract each other; this attraction is called an

Answer 8

ionic bond.

Question 9

In some cases, two atoms are so unequal in their attraction for valence electrons that the more electronegative atom strips an electron completely away from its partner. The two resulting oppositely charged atoms (or molecules) are called

Answer 9

ions.

Question 10

What has negligible mass?

Answer 10

Electron -is not taken into account for atomic mass calculations

Question 10

Hydrogen bonds are noncovalent bonds that result from an attraction between a hydrogen molecule that is already covalently bonded to an electronegative atom, and another electronegative atom. Hydrogen bonds thus form between molecules with partial opposite charges.

Answer 10

Hydrogen bonds occur when partial opposite charges on molecules come close enough to attract each other

Question 11

A covalent bond is likely to be polar if __________.

Answer 11

one of the atoms sharing electrons is much more electronegative

Question 12

If the atoms sharing electrons are equally electronegative, the electrons are shared equally and the bond is

Answer 12

nonpolar.
This would be the case, for example, for two atoms of the same element.

Question 13

Trace elements __________.

Answer 13

are required by an organism in minute quantities

Question 14

______ lead to changes in the composition of matter by making and breaking chemical bonds.

Answer 14

chemical reactions

Question 15

_______ exists when the forward and reverse rates of the reaction are equal; it does not depend on the amounts or concentrations of reactants and products.

Answer 15

Chemical equilibrium

Question 16

Because matter is being neither created nor destroyed, the number of particular atoms on either side of the reaction equation is

Answer 16

always the same.

Question 17

Any reactive atom or molecule that can react, not just organic molecules, can participate in a chemical reaction.

Answer 17

Any reactive atom or molecule that can react, not just organic molecules, can participate in a chemical reaction.

Question 18

Weak chemical bonds such as hydrogen bonds __________.

Answer 18

form when a hydrogen atom that is covalently bonded to an electronegative atom like oxygen or nitrogen is attracted to another electronegative atom

Question 19

both oxygen and nitrogen are _______ electronegative atoms.

Answer 19

strongly

Question 20

hydrogen ______ an electronegative atom.

Answer 20

is not

Question 21

_______ bonds are important in biological systems.

Answer 21

hydrogen

Question 22

When the proton number and electron number are unequal, the atom or molecule __________.

Answer 22

is an ion

Question 23

Isotopes of an element will always differ in __________.

Answer 23

atomic mass

Question 24

The atom has more electrons than protons.

Answer 24

Anion

Question 25

A ____ is an atom that has more protons than electrons and carries a positive charge

Answer 25

cation

Question 26

The difference between a stable isotope and an unstable isotope of an element is that __________.

Answer 26

the unstable isotope has a nucleus that decays spontaneously, is radioactive, and can be transformed into an atom of another element

Question 27

Stanley Miller's experiments were significant because he demonstrated that _________

Answer 27

a variety of simple organic compounds could be spontaneously synthesized from components in Earth's primitive atmosphere

Question 28

A straight-chain carbon compound constructed from __________ must contain at least one carbon-carbon double bond.

Answer 28

6 hydrogen atoms and 3 carbon atoms

Question 29

Ethanol, propanol, and methanol are three simple alcohols. They can be grouped together because they __________.

Answer 29

share the same functional group: a hydroxyl

Question 30

Functional group: Its compounds may be structural isomers with different properties.

Answer 30

carbonyl group

Question 31

Two carboxyl groups can bond covalently to help stabilize protein structure

Answer 31

sulfhydryl group.

Question 32

The covalent bond between oxygen and hydrogen is so polar that hydrogen ions tend to dissociate from oxygen reversibly.

Answer 32

carboxyl group.

Question 33

The functional groups is associated with a release of energy when removed from the carbon skeleton with water?

Answer 33

Phosphate group

Question 34

Which functional group would you predict is part of abscisic acid?

Answer 34

Carboxyl group

Question 35

Compounds containing the _______functional group (—COOH) are known as carboxylic acids or organic acids. They can donate a hydrogen ion (proton) to a solution due to a highly polar oxygen atom of the functional group.

Answer 35

Compounds containing the carboxyl functional group (—COOH) are known as carboxylic acids or organic acids. They can donate a hydrogen ion (proton) to a solution due to a highly polar oxygen atom of the functional group.

Question 36

The elements carbon, hydrogen, nitrogen, and oxygen make up ____% of living mass.

Answer 36

96%

Question 37

There are ___naturally occurring elements, and about ____ of these are essential to human life.

Answer 37

There are 92 naturally occurring elements, and about 25 of these are essential to human life.

Question 38

When one or more pairs of valence electrons are shared by two neutral atoms, what type of bond is formed?

Answer 38

Covalent bonds are formed between atoms that share one or more pairs of valence electrons.

Question 39

Pharmaceutical researchers are often interested in blocking particular receptor proteins on cell surfaces. What chemical property of a molecule would be most important for this type of application?

Answer 39

The molecule's shape

Question 40

describe a reversible reaction that has reached chemical equilibrium?

Answer 40

The rate of the reverse reaction equals the rate of the forward reaction.