Elements (SCI)

• There are 18 groups in the periodic table and 7 periods
• s & p block elements or A-GROUP elements are known as main group elements
• ALKALI METALS

  Group 1 :

  • Soft and shiny
  • Has an exothermic reaction
  • Very reactive
• ALKALINE EARTH METALS

  Group 2:

  • solid, shiny because they are metal
  • good conductors of electricity
  • high melting and boiling points
• TRANSITION METALS

  Group 3-12:

  • the D BLOCK elements
  • high thermal and electrical conductivity
  • very dense
  • these elements take on multiple charged states
• TRANSITION METALS (INNER)

  • Inner transition metals are called f block elements
  • Two classifications : Lanthanides and Actinides
• BORON GROUP - EARTH METALS

  
  

  Group 13:

  • Hard and brittle
  • Low melting point
  • Good conductors of heat and electricity
• Trends of the Periodic Table:

  • Ionization Energy: the amount of energy required to remove an electron from an atom or molecule
  • Electron Affinity: the change in energy when an electron is added to a neutral atom
  • Nonmetallic Characteristic: poor conductors of heat and electricity, and not malleable
  • Metallic Characteristic: metallic luster, shiny appearance, high density, high thermal conductivity, and high electrical conductivity
  • Atomic Radius: the total distance from an atom's nucleus to the outermost orbital of the electron
• Group 1: Alkali Metals:

  • Soft, shiny solids
  • Low density
  • Low melting point
  • Highly reactive to water
  • Exothermic reaction
  • Form cations with +1 charge
  • Hydrogen can form +1 or -1
• Group 2: Alkaline Earth Metals:

  • Solids, shiny, and conduct electricity
  • Harder than alkali metals
  • High melting points and boiling points
  • Exothermic reaction with water
• Groups 3-12: Transition Metals:

  • Hard and shiny solids
  • High thermal and electrical conductivity
  • Very dense
  • High melting points
  • Take on multiple charged states
• Group 13: Boron Group - Earth Metals:

  • Hard, brittle, and low melting point
  • Good electrical and thermal conductors
  • Forms +3 cations
• Group 14: Carbon Group - Tetrels:

  • Intermediate between metals and nonmetals
  • Ability of their atoms to form a network of chemical bonds
• Group 15: Nitrogen Group - Pnictogens:

  • Tendency to form stable compounds
  • Solid at room temperature except for nitrogen
• Group 16: Oxygen Group - Chalcogens:

  • Found in a wide variety of compounds
  • Varying/ unique physical and chemical properties
  • Stable and unreactive
• Group 17: Halogens:

  • Highly reactive
  • Toxic and potentially lethal
• Group 18: Noble Gases:

  • Not reactive and very stable
  • Low boiling points and odorless
• Review Questions:

  1. Ionization Energy is the amount of energy required to remove an electron from an atom or molecule

  2. Electron Affinity is the change in energy when an electron is added to a neutral atom

  3. Nonmetallic Characteristic shows poor conductors of heat and electricity, and are not malleable

  4. Metallic Characteristic shows metallic luster, shiny appearance, high density, high thermal conductivity, and high electrical conductivity

  5. Atomic Radius shows the total distance from an atom's nucleus to the outermost orbital of the electron
• Periodic trends are observable patterns in the properties of an element that depend on its position in the Periodic Table
• Electronegativity measures the tendency of an atom to attract electrons to form a bond
• Ionization energy is the minimum energy required to remove an electron from a neutral atom's outermost electron shell. This trend is the opposite of atomic radius's trend. The Ionization energy increases from the lower left to the upper right of the periodic table.
• Reactivity describes the ability of a molecule or atom to undergo a chemical reaction followed by a release in energy. It is dependent on characteristics such as electronegativity and ionization energy.
• Electron affinity describes the tendency of a neutral atom to gain an electron to form a negative ion. The trend increases from lower left to upper right, disregarding the noble gases.
• Atomic radius is the distance between an atom's nucleus and its outermost electron shell/orbital. It increases in size going down through its group. It decreases in size going left.
• Periodic law - states that when elements are grouped by atomic mass there is a periodic pattern in properties
• Which element has the highest ionization energy?

  Helium because it is on the top of the periodic table and its electrons are very near to the nucleus. Therefore, it requires more ionization energy.
• Which element has the highest atomic radius?

  Francium because it is on the lower left of the periodic table and shells are added as you go down the groups. [check definition for explanation]
• What element has the highest electron affinity?

  Fluorine because it is on the upper right (before noble gases) and if one more electron is given then it will have a full shell and have the same configuration as noble gases.
• Most metallic : group 1 , most nonmetallic : group 18