Chem 115 - The Representative Elements

Front 1

What describes the amount of energy required to remove an electron from the atom or molecule?

Back 1

Ionization energy

Front 2

The energy change associated with the addition of an electron to a gaseous atom is...

Back 2

Electron affinity

Front 3

The tendency of an atom in a molecule to attract shared electrons to itself is...

Back 3

Electronegativity

Front 4

The most dramatic differences between elements of the same group occur between...

Back 4

The first and second element

Front 5

T/F: Usually the first atom in a group is very small so it has a high electronegativity and forms covalent bonds instead of ionic bonds, which causes it to have sometimes amphoteric instead of basic properties, or perhaps to act as a metalloid instead of just as a metal or nonmetal.

Back 5

True

Front 6

T/F: Metallic character increases going down a group in the periodic table.

Back 6

True

Front 7

A covalent bond in which parallel p orbitals share an electron pair occupying the space above and below the line joining the atoms is a...

Back 7

Pi bond

Front 8

A covalent bond in which the electron pair is shared in an area centered on a line running between the atoms is a...

Back 8

Sigma bond

Front 9

T/F: "Like silicon atoms, the relatively large phosphorus atoms do not form strong pi bonds but prefer to achieve a noble gas configuration by forming single bonds to several other phosphorus atoms"

Back 9

True

Front 10

The process of obtaining a metal from is ore is called...

Back 10

Metallurgy

Front 11

Since the metals in ores are found in the form of cations, what does the chemistry of metallurgy almost always involve? Which reducing agent is usually used?

Back 11

The reduction of the ions to the elemental metal (with an oxidation state of zero). Carbon.

Front 12

Elemental nitrogen and oxygen are usually obtained from the...

Back 12

Liquefaction of air (based on the principle that a gas cools as it expands)

Front 13

Although, as was established in the notebook, Lithium is the strongest 1A reducing agent, it reacts with water slowest. Why?

Back 13

Because, as a solid, Li has a high melting point than the other 1As (Na, K) and so it does not become molten from the heat of reaction with water (as Na and K do) so it has a smaller area of contact with the water.

Front 14

Binary compounds containing hydrogen are called...

Back 14

Hydrides

Front 15

What type of hyrdride forms with H and group 1A or 2A elements? Briefly characterize it.

Back 15

Ionic hydride, produces H-, strong reducing agent because 1s orbital has two electrons and is small

Front 16

What type of hydride forms a covalent bond with H and another non metal?

Back 16

Covalent hydride

Front 17

What type of hydride consists of a transition metal bombarded with H2 gas so that the H2 splits into two H atoms and fills the holes in the transition metal?

Back 17

Metall or interstitial hydrides

Front 18

Covalent hydrides with boron are called...

Back 18

Borane (most stable B2H6)

Front 19

What is the compromise between thermodynamics and kinetics in the Haber process?

Back 19

High pressure to force the reaction to the right (towards ammonia) and high temperature so that the reaction occurs at a reasonable rate.

Front 20

The process of transforming inert N2 to other nitrogen-containing compounds is called...

Back 20

Nitrogen fixation (haber process is actually an example of this, so is the combustion process in automobile engines)

Front 21

The return of nitrogen from decomposed matter to the atmosphere by bacteria that change nitrates to nitrogen gas is called...

Back 21

Denitrification

Front 22

By far the most important hyrdide of N is...

Back 22

Ammonia (NH3)

Front 23

What does a high boiling point signify about nitrogen hydrides?

Back 23

That there is significant hydrogen bonding that occurs to make the BP higher even though the molar mass is pretty low.

Front 24

What occurs in the Ostwald process?

Back 24

The oxidation of of ammonia for making nitric acid

Front 25

T/F: Those members of group 6A (Oxygen, sulfur, etc.) that have d orbitals available (all but Oxygen) commonly form molecules in which they are surrounded by more than 8 electrons (violate the octect rule).

Back 25

True

Front 26

Which oxyacid of sulfur is an incredibly strong dehydrating agent?

Back 26

H2SO4 (sulfuric acid)

Front 27

When a metal ion is in a higher oxidation state, such as +3 or +4, the metal-halogen bonds are...

Back 27

Polar and covalent

Front 28

When dissolved in water, the hydrogen halides behave as _, and all except _ are completely dissociated.

Back 28

acids; HF of course. All of these acids are strong except for HF which is weak

Front 29

What is the conflict between the bond energy and the enthalpy of hydration for the acidity of HF?

Back 29

HF has the highest bond energy (which would make it a weaker acid) but an enthalpy of hydration which (because it's very negative) favors the dissociation of HF more than any of the other hydrogen halides.

Front 30

So, what then actually accounts for HF's weak acidity?

Back 30

It's ENTROPY of hydration, because when HF dissociates it has a very negative (and thus unfavorable) entropy reaction with water which favors order and thus does not favor the law of the universe. This outweighs everything.

Front 31

Which is the most important of the hydrohalic acids?

Back 31

Hydrochloric acid

Front 32

The strengths of the halogen oxyacids vary in direct proportion to the number of oxygen atoms attached to the halogen, with the acid strength increasing as...

Back 32

More oxygens are added

Front 33

A reaction in which an element is both oxidized and reduced is called a...

Back 33

Disproportionation reaction

Front 34

T/F: The alpha particle is a helium nucleus that can easily pick up electrons from the environment to form a helium atom.

Back 34

True