AS INORGANIC CHEMISTRY Flashcards
What is the atomic radius?
It is the distance between the
What is the atomic radius?
It is the distance between the nucleus and the outermost electron
What is the trend of atomic radius across a period?
It decreases
why are metal ions smaller than their atoms?
- The Cations have lost their valence electrons
What is the trend in the ions going from Na+ to Si4+
They get smaller due to the increasing nuclear charge attracting the electrons in the second principle quantum shell.
Why are anions smaller than their original atoms?
because each atom has gained one or more electrons in its third quantum shell.
this increases the repulsion while the nuclear charge stays the same.
Why does Silicon have the highest melting point?
Each Si is covalently bonded to the neighbouring Si atoms.
What is the trend of melting points for period 3 metals?
They increase
Why does melting point increase for period 3 metals?
Because the electrostatic forces between the cations and the sea of free delocalized electrons gets stronger.
What is the bonds between the covalent molecules
instantaneous dipole- induced dipole forces
Why does electrical conductivity increase going from Na to Al?
Because there is an increase in the valence electrons going into the sea of delocalized electrons.
This means that there are more electrons to move around when they are conducting electricity.
Why is Si not a good electrical conductor?
Since it forms a giant molecular structure, there are no free electrons to move around within the structure.
It is therefore classified as a semimetal.
What is the first ionization energy?
It is the energy required to remove one mole of electrons from one mole of the element in the gaseous state to form one mole of gaseous electrons.
What is the general trend in the first ionization energy across Period 3?
It increases
Why is there a general increase in the first ionization energy across period 3?
- Nuclear charge increases
- The atomic radius decreases
- There are stronger attractions between the nucleus and the outer electrons.
- It, therefore, gets harder to remove the outer electrons.
Where are dips found in the trend of first ionization energy?
Mg - Al
P - S
What is ceramic?
It is a rigid material that is made up of an infinite 3D network of sintered metals bonded to carbon, nitrogen and oxygen.
What is sintering?
It is when a powdered material is heated below its melting point, which results in the formation of new bonds between the powder grains to form one large mass.
What are some examples of ceramics?
- Magnesium oxide
- Aluminium oxide
- Silicon dioxide
Why are ceramics hard and brittle?
Hard: They have strong bonds and forces that hold the atoms and ions together in the 3D structure.
Brittle: If the 3D structure is distorted, the ceramic will easily break.
Why do ceramics have very high melting points
They have strong covalent or ionic bonds in the structure also means that ceramics have high melting points.
A lot of energy is required to break these bonds.
Why are Ceramics good insulators?
Covalently bonded ceramics have no free electrons
Ionic bonded ceramics have no ions that can freely move around.
What are the applications of Magnesium oxide as a Ceramic?
- Furnace linings due to their high melting points
2. Heating elements - for example, electrical cookers as ceramics are good electrical insulators.
What are the applications of Aluminium Oxide as a ceramic?
- High temperature and voltage electrical insulators due to their high melting and electrical insulating properties.
- Replacement Hip joints as they are highly durable
