Main Group Chemistry Flashcards
What are the main group chemistry blocks?
s and p
Which elements are anomalous in their behaviour?
second period
Which elements are representative of their group?
third period
What are the reasons for the anomalies?
1) Small size and high electronegatively
2) Maximum of four covalent bonds (no d orbitals for bonding)
3) More common occurrence of multiple bonding (good pie overlap of 2p orbitals)
Why do elements within the same group exhibit similar behaviours?
Because of the similar valence electron configurations
Group 13 name?
Triels
Group 15 name?
Pnictogens
Group 16 name?
Chalogens
What kind of behaviour increases as down a group
metallic
Which element does not have a perfectly suitable position in the periodic table?
Hydrogen
What properties does hydrogen have?
Very reactive and combines with nearly every other element
What unique properties does alkali metals have?
- usually soft
-Lower melting and boiling points and densities compared to other metals
What is the hydride ion (H-) powerful at?
Being a reducing agent
What metal reacts vigorously in water?
Potassium
Alkali metals are ______ reactive and are powerful ___________ agents
extremely
reducing
In what kind of reactions does alkali metals reduce halogens
highly exothermic reactions
What properties does alkaline earth metals have?
- harder and higher melting points
- somewhat less reactive
What is the use of CaCO3?
- heated to obtain calcium oxide (lime)
- lime has essential roles in steelmaking, water treatment, and smokestack scrubbing
- lime is used to make glass, whiten paper, and neutralize acidic soil
How is Be a unique alkaline earth metal?
- un-reactive in air and water
- BeO is an amphoteric oxide (can act as an acid or a base in a reaction)
- Be compounds have strong covalent character AND conduct electricity poorly in the molten state
What is cesium used for?
- in atomic clocks
- photovoltaic cells
- night vision equipment
What is strontium used for?
- used in fireworks
- in signal flares
What is Be and Mg used for?
- used in manufacture of alloys
- Mg- Al alloys are used in the construction of aircrafts
What is barium used for?
- Barium sulfate is used in x rays to detect problems in the digestive tract (insoluble in water - coats the esophagus, stomach, and intestines)
- Barium nitrate and barium chlorate are used in fireworks
- used in paint pigments
Boron description
- metalloid
- has a covalent network structure
- is black, hard and high melting point
What mineral does boron occur naturally?
- borax
What feature does most boron containing compounds have?
- electron deficiency
application of boron compounds
- pyrex glass
- sodium perborate (colour safe bleach)
- boric acid ( cockroach insecticide
Characteristics of aluminum
- metal
- occurs naturally in the mineral bauxite
Which group 13 element is smaller then Al
Ga
How is Al2O3 converted to Al?
reduction process, carried out by electrolysis
What is the process of converting Al2O3 to Al called?
Hall-Heroult
Characteristics of N2
- colourless gas
- Very inert
Characteristics of P4
- white
- waxy
- toxic
- highly reactive
- phosphorescent
Characteristics of P
- red
- non toxic
- less reactive
How is nitrogen isolated?
By fractional distillation of liquid air
Uses of nitrogen?
- A cryogen
- inert atmosphere
Examples of hydrides
NH3 and PH3
Properties of NH3
- colourless gas
- prepared by haber process
- used as fertilizer and base
Properties of PH3
- Extremely toxic gas
- weaker base than NH3
Properties of dinitrogen monoxide
- colourless, sweet-smelling gas
- dental anesthetic
- propellant for whipped cream
Properties of nitrogen monoxide
- colourless, paramagnetic gas
- air pollutant, neural transmitter
Properties of nitrogen dioxide
- brown, toxic gas
- photochemical smog
- formed by reaction of NO + O2
Difference in P4O6 and P4O10
P4O6 –> formed by limited O2
P4O10 –> formed by excess O2
What are the two allotropes of oxygen?
- O2
- O3
properties of O2
- colourless
- paramagnetic gas
Properties of O3
- bluish
- pungent
- diamagnetic gas
Industrial uses of oxygen
- steel production
- chemical manufacture
- sewage treatment
- oxidizer for rocket fuels
What forms acid rain?
sulfur –> H2SO4
What is the worlds most important industrial chemical?
Sulfuric acid
What does sulphuric acid do?
is an excellent dehydrating agent
