Mock Questions Flashcards
Why does silicom have a high melting point?
It has a gaint lattice structure - the covalent bonds are strong throughout it.
A lot of energy is required to overcome the attractions between the atoms
Why does magnesium have a higher melting point than sodium?
Magnesium ions are smaller than sodoium ioms and have a greater charge (therefore larger charge density) thus the attraction between the positive ions and delocalised electrons is stronger in magnesium than in sodium
Explain why the first ionisation energy of helium is higher than that of hydrogen?
The helium atom has a higher nuclear charge.
Explain why the chemical properties of the elements in group 1 are very similar ?
The outer electronic configurations of the atoms are identical with one electron in s-orbital
Why is the first I.E of boron less than that of beryllium even though a boron atom has a greater nuclear charge?
The outer electron of boron has higher energy since it is in a 2p orbital as opposed to the 2s orbital for beryllium furthermore the boron electeons experiences greater shielding.
