Elements in periodic table

1
Elements in periodic table

• With so many elements already found and the
  possibility of more being discovered, chemists
  needed a way to organize them. Many systems were
  tried in order to make some sort of pattern in
  their properties to match the table. The modern
  periodic table, based on atomic number and
  electron configuration, was created primarily by
  a Russian chemist, Dmitri Ivanovich Mendeleev,
  and a German physicist, Julius Lothar Meyer, both
  working independently. They both created similar
  periodic tables only a few months apart in 1869.
  Mendeleev created the first periodic table based
  on atomic weight. He observed that many elements
  had similar properties, and that they occur
  periodically, hence the name, periodic table. The
  modern periodic table elements are ordered by
  atomic number ( number of protons in the
  nucleus), not weight. For example, the elements
  lithium, sodium, potassium, rubidium, and cesium
  have similar chemical properties. The elements
  that immediate follow them, beryllium, magnesium,
  calcium, strontium, and barium, also have similar
  chemical properties. Elements in Mendeleev's
  table were arranged in rows called periods. The
  columns were called groups. Elements of each
  group had similar properties.

2
Nonmetals

• Nonmetals
• the elements that lack the properties of metals
  most often encountered as compounds or mixtures
  of compounds
• some occur in their elemental forms and are very
  important e.g. Nitrogen (N2), oxygen (O2),
  carbon.
• Properties
• almost completely opposite of metals poor
  conductors of heat and electricity (except for
  graphite -- attributed to molecular structure).
• Many are solids at STP, while many others are
  gases.
• All of the group 0 (18) elements (the noble
  gases--mostly inert) are
  gases consisting of single atoms.
• all other gaseous elements, hydrogen, oxygen,
  nitrogen, fluorine, and chlorine, are diatomic
  molecules--H2, O2, N2, F2, and Cl2.
• Bromine and iodine are also diatomic, but bromine
  is a liquid and iodine is a solid at room
  temperature.
• nonmetals also lack the malleability and
  ductility of the metals -- brittle
• wide range of reactivity
• Flourine is extremely reactive, reacting readily
  with almost all other elements.
• Helium is inert and does not react with anything.
  

3
Metalloids

• Metalloids are the elements found along the
  stair-step line that distinguishes metals from
  non-metals. This line is drawn from between Boron
  and Aluminum to the border between Polonium and
  Astatine
• (exception Aluminum -- classified under "Other
  Metals)
• list of metalloids
• B Boron,
• Si Silicon,
• Ge Germanium,
• As Arsenic,
• Sb Antimony,
• Te Tellurium,
• Po Polonium
• properties between those of metals and nonmetals.
  Generally, metalloids behave as nonmetals, both
  chemically and physically.
• They are semiconductors conduct electricity,
  but not as well as metals.
• e.g. silicon and germanium, used in solid-state
  electronics transistors made from semiconductors
  have reduced the size of electronic components to
  an almost microscopic level

4
Representative metals

• The representative metals contain 3 main groups
• alkali metals
• alkaline earth metals,
• post-transitional metals.
• Alkali Metals
• group IA (1) elements in the table
• form hydroxides which are strongly basic (e.g.,
  potassium hydroxide--KOH), hence the term
  "alkaline"
• have a very high metallic behavior and are good
  reducing agents.
• crystallize with a body-centered cubic lattice in
  which the points are occupied by 1 ions.
• sea of valence electrons throughout the entire
  lattice can wander throughout the metal ?high
  electrical conductivity and high heat
  conductivity.
• high luster is due to the highly mobile electrons
  of the lattice. Light beams hit the electrons
  into oscillations, reflecting back
  electromagnetic energy as light. The softness,
  malleability, and ductility of the metals are due
  to the nature of the forces holding the lattice
  together. Since there is no net force or
  attraction between the ions, they can be moved
  from one lattice site to another.

5
The Alkaline Earth Metals

• The alkaline earth metals are metallic elements
  in the group IIA (2) of the periodic table. They
  are called alkaline earth metals because the
  "earths" of this group, lime (CaO), and magnesia
  (MgO), give alkaline reactions.
• All alkaline earth elements have an oxidation
  number of 2, making them very reactive. Because
  of their reactivity, the alkaline metals arenot
  found free in nature.
• They have good metallic
  properties, including
  conductivity, reduction
  ability, luster, softness,
  malleability, and ductility,
  but not as well as the alkali
  metals. Their ions have an oxidation state of
  2. Like alkali metals, they form soluble
  sulfides, but unlike them, they form insoluble
  carbonates (calcium
  carbonate -- CaCO3 -- in
• hard water).
• List of alkaline earth metals
• Be Beryllium
• Mg Magnesium
• Ca Calcium
• Sr Strontium
• Ba Barium
• Ra Radium

6
The Post-Transition Metals

• The post-transition metals the lower elements
  of group IIIA (13), IVA (14), and VA (15),
  arranged in a staircase like fashion.
• Their properties have the same relationship to
  the alkaline earth metals
  as the
  alkaline earth metals have to the alkali metals..
  As you go up the
  group, their
  metallic character gets less and less.
  
  For example boron, which is above aluminum
  in group IIIA (13), is not a metal but
  
  a metalloid.
• While these elements are ductile and malleable,
  they are not the same as the transition
  elements.These elements, unlike the transition
  elements, do not exhibit variable oxidation
  states, and their valence electrons are only
  present in their outer shell. All of these
  elements aresolid, have a relatively high
  density, and are opaque. They have oxidation
  numbers of 3, 4, and -3.
• List of post-transition metals
• group IIIA (13) Al Aluminum, Ga Gallium, In
  Indium, Tl Thallium
• group IVA (14) Sn Tin, Pb Lead
• group VA 15) Bi Bismuth

7
Transition metals

• The 38 elements in groups 3 through 12 of the
  periodic table are called "transition metals". As
  with all metals, the transition elements are both
  ductile and malleable, and conduct electricity
  and heat. The interesting thing about transition
  metals is that their valence electrons, or the
  electrons they use to combine with other
  elements, are present in more than one shell.
  This is the reason why they often exhibit several
  common oxidation states.
• three noteworthy elements in the transition
  metals family iron, cobalt, and nickel -- are
  the only elements known to produce a magnetic
  field (i.e. that can be magnetized)
• The transition metals are the subgroups of
  elements intervening between groups IIA(2) and
  IIIA(13) in the periodic table. They are
  classified separately because of the filling of
  their d subshell orbitals.
• All the transition elements are metallic, but
  unlike the representative metals, they are likely
  to be hard, brittle, and have high melting points
  because of the relatively small size of their
  atoms and the existence of some covalent binding
  between ions. There are exceptions, as in the
  case of mercury (Hg), which is a liquid. They
  have high electrical conductivity because of
  delocalization of the s electrons similar to what
  occurs in the alkali and alkaline-earth metals.

8
Transition metals, contd

• transition metals have a great variety of
  oxidation states shown in its compounds. Because
  of electron spin, unpaired electrons give rise to
  paramagnetism. Paramagnetism is likely in
  transition metals because of the partial filling
  of the d subshell and the movement associated
  with the orientations of electrons.
• Color of transition metals (and some of their
  ionic compounds) due to absorption of some of
  the frequencies of white light ? electronic
  transitions in the d subshell. The stored energy
  is then dissipated through heat.
• transition metals also have complex ionic
  structures because of the availability of d
  orbitals
  for participating in chemical bonding.
• List of transition metals
  ScScandium Ti Titanium V Vanadium Cr
  Chromium Mn Manganese Fe Iron Co
  Cobalt Ni Nickel Cu Copper Zn Zinc
  Y Yttrium Zr Zirconium Nb Niobium Mo
  Molybdenum Tc Technetium Ru Ruthenium Rh
  Rhodium Pd Palladium Ag Silver Cd
  Cadmium La Lanthanum Hf Hafnium Ta Tantalum
  W Tungsten Rh Rhenium Os Osmium Ir
  Iridium Pt Platinum Au Gold Hg
  Mercury Ac Actinium

9
Inner transition (rare earth) metals

• thirty inner transition metals (also called rare
  earth elements) contain 2 series of elements
• lanthanide series,
• actinide series.
• All of them in group 3 of the periodic table, and
  the 6th and 7th periods.
• One element of the lanthanide series and most of
  the elements in the actinide series are called
  trans-uranium, which means synthetic or man-made.
  

10
Lanthanide series

• The lanthanide series include the 15 elements
  from atomic numbers 57 (lanthanum) to 71
  (lutetium). Their electron configuration include
  the 4f and 5d energy levels. Because of the
  closeness of those two levels, there is
  considerable uncertainty in some electron
  configuration assignments. All the lanthanides
  form 3 ions as their principal chemical species.
  It is assumed that the ions are formed by losing
  the 6s2 and 5d1 (or 4f is 5d is not present)
  electrons. They generally occur together, except
  for promethium which has an unstable nucleus. The
  richest source mineral is monazite, a complex
  phosphate. They are very rare to find, hence
  their nickname--"the rare earth elements." Since
  they also have very similar chemical properties,
  separation is very difficult, involving
  fractional crystallization and ion-exchange
  techniques. The lanthanides also generally have
  an incomplete 4f subshell, resulting in
  paramagnetism.
• List of lanthanides La Lanthanum Ce
  Cerium Pr Praseodymium Nd Neodymium Pm
  Promethium Sm Samarium Eu Europium Gd
  Gadolinium Tb Terbium Ds Dysprosium Ho
  Holmium Er Erbium Tm Thulium Yb Ytterbium
  Lu Lutetium

11
The Actinide series

• The actinide series include the 14 elements that
  
  follow actinium (atomic number 89) from atomic
  
  numbers 90 to 103. The electron configurations of
  
  the actinides are even more uncertain than the
  
  lanthanides because the closeness of the energy
  
  levels and because the nuclei are unstable to
  
  radioactive decay. Only minute amounts of some
  
  elements are obtained because of their
  instability.
  All of the actinides are unstable with
  respect to
  alpha emission. The later members tend
  to undergo
  spontaneous fission, a fact which limits
  the number
  of elements possible. The actinides also
  seem to
  show a variety of oxidation states, unlike
  the
  lanthanides. Uranium, for example, has
  compounds
  in each of the states, 3, 4, 5, and
  6.
• Lu Lutetium Thorium (Th) Pa Protactinium U
  Uranium (U) Np Neptunium Pu
  Plutonium Am Americium Cm Curium
  Bk Berkelium Cf Californium
  Es Einsteinium Fm Fermium
  Md Mendelevium No Nobelium Lr Lawrencium