ch 18 main group elements

representative elements

chemical properties are determined by the valence-level s and p electrons

transition metals

results from the filling of the d orbitals

lanthanides

correspond to the filling of 4f orbitals

actinides

correspong to the filling of the 5f oribitals

metalloids

elements along the division line between metals and nonmetals in the periodic table

metals

elements that lose valence electrons to form cations with the goal of exhibiting the e- configuration of the noble gas from the previous period

nonmetals

elements that gain valence electrons to form anions with the goal of exhibiting the e- configuration the noble gas in the same period

common theme between the first element of each period

each first metal of a period has a dramatically smaller atomic radii between the first and second which leads the first having different characteristics from the others.

differentiates H from other group 1a elements

hydrogen is a nonmetal and can form covalent bonds w/ nonmetals, other group 1a elements are highly reactive metals that form ionic bonds w/ nonmetals

differentiates Be from other group 2a elements

beryllium does forms an amphoteric oxide with oxygen, all other group 2a metals form basic oxides

differentiates B from other group 3a metals

boron acts mostly as a nonmental, all other group 3a metals are active metals

differentiates C from Si in group 4a

carbon compounds mainly have c-c bonds, since they’re strong. silicon mainly has si-o bonds since their si-si bonds aren’t that strong

metallurgy

process of obtaining a metal from its ore

most abundant nonmetal in the planet

oxygen

most abundant metal in the planet

aluminum

how are most active metals reduced/prepared?

electrolysis

how are oxygen and nitrogen typically prepared?

they are converted to liquid through liquefaction and separated by distilling liquid air

what electron configuration do group 1a elements typically have?

ns¹

what are the names of group 1a elements?

alkali metals

what is a quality of group 1a elements?

they are highly reactive, especially with water

which group are essential for the functioning of nerves and muscles

group 1a, especially Na and K

how are Na, Li, and K prepared?

electrolysis of their chloride

2M + X₂ → 2MX; 2M + 2H₂O + H₂

common reactions of alkali metals

how are Rb and Cs prepared?

Through the reduction of their oxide with Mg and H

oxide ion

O^2-

peroxide ion

O₂^2-

superoxide ion

O₂^-

which alkali metals form oxides?

lithium

which alkali metals form peroxides?

sodium

which alkali metals form superoxides?

calcium, rubidium, and cesium

what are the physical properties of hydrogen?

hydrogen is a colorless, odorless diatomic gas. it has a low molar mass, boiling, and melting point. it is non polar and highly flammable

what are the sources of hydrogen?

industrially when water reacts with methane. through electrolysis of water and as a by product of gasoline production.

what is an industrial use of hydrogen?

production of ammonia by the haber process

what is another use of hydrogen?

hydrogenation of unsaturated vegetable oils to produce saturated and solid shortenings (which have C-C single bonds)

what does hydrogen behave as?

nonmetal

what does hydrogen form with nonmetals?

covalent compounds

what does hydrogen form with active metals?

salts

hydride

binary compounds containing hydrogen

ionic hydrides

formed when hydrogen combines with the most active metal (group 1a and 2a)

what does the hydride ion act as?

strong reducing agent (strong base)

covalent hydride

forms when hydrogen combines with nonmetals

what is the most important covalent hydride?

water

what are unusual properties of water?

high boiling point, large heat of vaporization, higher density in liquid form than in solid form, excellent solvent for ionic and polar substances

metallic hydrides

formed when small hydrogen atoms migrate into the crystal structure occupy interstices (holes)

what happens when a metallic hydride is heated?

the hydrogen gas is released when heated which gives hydrogen to be used as portable fuel

what are group 2a elements called?

alkaline earth metals

what is the val e- configuration of group 2a elements?

ns²

what are qualities of group 2a metals?

they are very reactive

how do Ca, Sr, and Ba react with water at 25 degrees C?

they react vigorously

how do Mg and Be react with water at 25 degrees C?

show no reaction so they are more difficult to oxidize

how is Ca applied?

it is found in the structural minerals that compose bones and teeth?

how is Mg (Mg²⁺) applied?

essentially in metabolism and muscle function and useful structural material because of its low density and moderate strength

how are group 2a elements prepared?

they are prepared through the electrolysis of their chlorides

M+X₂ → MX₂ ; 2M + O₂ → 2MO ; M + 2H₂O → M(OH)₂ + H₂

common reactions of group 2a elements

hard water

natural water that has Ca²⁺ and Mg²⁺ which interferes with the action of detergents and form precipitates with soap

ion exchange

process that removes Ca²⁺ and Mg²⁺ in individual homes (water softener)

ion exchange resins

consists of large molecules (polymers) that have many ionic sites

what are group 3a elements called?

boron group

what is a trend in group 3a metals?

increase an increase in metallic character in going down the group

what is the val e- configuration of 3a elements?

ns²np¹

what are boranes?

covalent hydride compounds of boron

what is the simplest borane?

B₂H₆

how do boranes react with oxygen?

boranes react exothermically with oxygen and was once evaluated for rockets in the U.S. space program

how is B prepared?

reduction by Mg or H₂

how is Al and Tl prepared?

electrolysis

how is Ga and Id prepared?

reduction with H₂ and electrolysis

what is a property of gallium

it has the largest liquid range of any metal with a low melting point and high boiling point

what are the properties of aluminum

it has metallic properties but can form covalent bonds with nonmetals

what is a property of thallium?

thallium’s chemistry is completely metallic

2M + 3X₂ → 2MX₃

common reaction for group 3a elements; Tl gives TlX but not TlI₃

4M + 3O₂ → 2M₂O₃

reaction for group 3a element at high temperatures, Tl gives Tl₂O as well

what are group 4a elements called?

carbon group

what is the val electron configuration for group 4a elements?

ns²np²

what does carbon include?

carbon includes the fundamental constituent of molecules that are necessary for life

what does silicon form?

silicon forms the basis for the geological world

how many covalent bonds do group 4a elements form?

group 4a elements form four covalent bonds

what special bonds can carbon and no other 4a element make?

carbon can form pi bonds (double and triple bonds)

where does carbon occur?

the allopatric forms of graphite, diamond, and fullerenes

what are properties of germanium?

germanium is used in the manufacturing of semiconductors and transistors

what are the properties of tin?

tin is used in alloys as a protective coating for steel. SnCl₂ is a famous reducing agent

what is tin disease?

tin cans, when exposed to low temperatures can turn powdery gray and crumble which contaminates food

what are properties of lead?

lead melts at low temperatures and is very toxic in nature

M + 2X₂→ MX₄; M+ O₂

common reactions with group 4a elements

what are group 5a elements called?

pnictogens

what is the val electron configuration of group 5a elements?

ns²np³

how do the chemical properties vary in group 5a elements?

in group 5a elements, metallic character increases going down the group

which group 5a elements are nonmetals?

nitrogen and phosphorus, they form 3^- anions

which group 5a elements are metals?

bismuth and antimony exhibit metallic properties, they can lose electrons to form cations

how many covalent bonds/ions can group 5a elements form?

group 5a elements can form 3,5 or 6 covalent bonds

what are properties of group 5a elements with 3 covalent bonds?

have a lone pair so they can act as lewis bases

what is the VSEPR of group 5a elements with 3 bonds?

pyramidal

how is nitrogen prepared?

nitrogen is prepared through the liquefaction of air

what bond does N₂ have?

a strong triple bond

what are properties of N₂?

N₂ is unreactive and a useful medium for experiments conducted using an inert atmosphere box

what does the stability of N₂ contribute to?

the stability of N₂ contributes ti the power of explosives. Little amounts of nitrogen can produce tons of moles of gaseous profducts?

what are some examples of nitrogen based explosives?

nitroglycerin (C₅H₅N₃O₉) and trinitrotoluene (TNT)

what is nitrogen fixation?

nitrogen fixation is the process of transforming N₂ to other nitrogen containing compounds

what is the haber process?

a form of nitrogen fixation used to manufacture ammonia

how are nitrogen fixation and combustion related?

nitrogen fixation can result from high-temp combustion that occurs in car engines. when nitrogen in the air is drawn into the engine, it reacts with oxygen to form nitric oxide which further reacts with oxygen to form nitrogen dioxide a form of photochemical smog

how does nitrogen fixation occur in nature?

nitrogen fixing bacteria converts nitrogen to ammonia for plants