Transcript Chemistry 11: Typical Elements Christopher Chui 5/27/2016

Chemistry 11:
Typical Elements
Christopher Chui
5/27/2016
Typical Elements -- C. Chui
1
Hydrogen







Members of a family or group tend to react similarly
Hydrogen is usually considered as a family by itself
A hydrogen atom can react to lose 1 electronH+
A hydrogen atom can also share its electron with
nonmetals, such as HCl or H2O
The 3rd way is that a hydrogen atom gains 1 electron
to become a hydride ion, HA 4th way is to form bridges, such as boron hydride,
B5H9
A 5th way is to add hydrogen to the double bonds of
carbon in organic chemistry
5/27/2016
Typical Elements -- C. Chui
2
Alkali Metals






The alkali metal atoms increase in size with
increasing atomic number: Li, Na, K, Rb, Cs, Fr
As the atomic numbers increase: atoms become
larger; outer electrons are farther from nucleus;
lower level electrons shield effect of larger nucleus;
outer electrons are held less tightly; and atoms
become more active
Sodium compounds are used as catalysts and in the
production of paper, glass, detergents, soaps,
pigments, and petroleum products
A catalyst is a substance that speeds up a reaction
Lithium is used to make batteries. It forms the 1+ ion
Alkali metals form binary compounds with most
nonmetals
5/27/2016
Typical Elements -- C. Chui
3
Alkali Earth Metals






Alkaline earth metals form the 2+ ion
Most group 2 (IIA) compounds are soluble in water
The metals (Ca, Sr, Ba, Ra) will displace hydrogen
from water and other compounds
Calcium oxide (lime) is used to make steel, cement,
and heat-resistant bricks
Calcium chloride is used in making paper and pulp
Calcium is important in the structure of bones and
teeth. Calcium ions are necessary for the contraction
of muscles. Calcium ions also take part in the
reaction that cause blood to clot
5/27/2016
Typical Elements -- C. Chui
4
Aluminum, and Carbon












Aluminum is the most plentiful metal in Earth’s crust
Aluminum (Gp 13, IIIA) tends to share its 3 outer electrons in
forming compounds
Aluminum sulfate is used in water purification, paper
manufacture, and fabric dyeing
Carbon (Gp 14, IVA) reacts by sharing 4 electrons
Carbon forms long chains by catenation
Diamond and graphite are 2 allotropes of carbon
Carbon dioxide is used in refrigeration, beverages, and in
making other chemicals
Small crystals of dry ice are used in cloud-seeding
Silicon is the 2nd most plentiful element in Earth’s crust
Silicon bonds by sharing electrons
Tin: 4+ is more stable than 2+; and lead: 2+ is more stable than
4+.
5/27/2016
Typical Elements -- C. Chui
5
Nitrogen and Phosphorus










N2 and P4 are found in Gp 15 (VA)
N2 occurs in oxidation states from 3- through 5+
P4 occurs only in 3-, 0, 3+, and 5+
N2 gas is very stable, but its compounds are not
TNT and dynamite are made with N2
Liquid N2 has extensive industrial use
Ammonium nitrate is used as fertilizer or explosives
P4 molecules stack in different ways to form
allotropes
Phosphoric acid is used to make fertilizer and other
applications
Organic compounds of phosphorus are vital to living
organisms
5/27/2016
Typical Elements -- C. Chui
6
Oxygen Family







Oxygen is the most plentiful element in Earth’s crust
Oxygen reacts by gaining 2 electrons or by sharing
electrons
It loses electrons with metals to form ionic oxides.
Ionic oxides react with H2O to form basic solutions
It shares electrons with nonmetals. The nonmetallic
oxides react with H2O to form acidic solutions. This
dual behavior is called amphoteric
O2 has several allotropes. Their properties are
similar to that of sulphur
S can form long chain ions such as S6 2Other members of the group: Se, Te, and Po
5/27/2016
Typical Elements -- C. Chui
7
Halogens






Group 17 (VIIA) contains F, Cl, Br, I, and As
Halogens react by forming negative ions or by
sharing electrons
As the atomic numbers increase: atoms become
larger; outer electrons are farther from nucleus;
lower level electrons shield effect of larger nucleus;
nucleus has less attraction for electrons of other
atoms; and atoms become less active
F is the most reactive chemical element
Cl forms chlorides readily. The primary use of Cl is to
make other chemicals
Halogens form compounds such as CIF, ClF5, BrF5,
IF5, IF7, BrCl, and ICl3
5/27/2016
Typical Elements -- C. Chui
8
Noble Gases






Group 18 (VIIIA) contains very stable gases,
because all outer electrons are filled
Chemically, noble gases are not inert
Xe, Kr, and Rn compounds have been made
Xenon hexafluoroplatinate (XePtF6) was first made
in 1962
Ar is used to fill light bulbs to protect the filament
Ne, Kr, and Xe are used to fill brightly colored gas
discharge tubes for advertising
5/27/2016
Typical Elements -- C. Chui
9
Transition Metals-1



Transition elements have electrons filling d
sublevels
Transition metals have many uses. Au, Ag, Cu, Ni,
and Pt are coinage metals. Catalytic converters
contain Pt, Pa, and Rh. Os is used to harden pen
points. Co-60 is used to treat cancer. Mo is used in
spark plugs
Transition elements, used alone or as alloys, are
our principal structural metals: Ti through Zn. TiO2
is used in paints. MnO2 is used in batteries. Fe and
Cr oxides are used in audiotapes and videotapes
5/27/2016
Typical Elements -- C. Chui
10
Transition Metals-2






Cr is important because it resists corrosion. It is used
in stainless steel and chromeplate regular steel
Cr reacts by losing 3 electrons to form the Cr 3+ ion
Cr also forms the 6+ states in CrO4 2- , and Cr2O7 2Many Cr compounds are colored. Small amount of
Cr are found in crystals of rubies and emeralds
Zn behaves different because of its full d sublevel. It
has one oxidation state, 2+
Metallic Zn is corrosion resistant. It is used to coat
Fe. This process is called galvanizing
Zn is essential to proper body function
5/27/2016
Typical Elements -- C. Chui
11
Neodymium (Lanthanoid), Curium (Actinoid)






Nd, as all lanthanoids, shows 3+ as the most stable
oxidation state
Nd metal is soft and very reactive. It forms alloys
with unusual conductivity and magnetic properties.
Nd2O3 is used in glass filters and in lasers
Curium (Cm) has a half-full f sublevel. It forms 3+
oxidation compounds. Its solution is pale yellow
Cm is a slivery, hard metal of medium density and
high melting point. It does not occur in nature. It is
produced by slow neutron bombardment of Pu
Cm is reactive and highly toxic to humans
Cm is used as energy source in satellites
5/27/2016
Typical Elements -- C. Chui
12