Answer:
the octet rule is based on the fact that filling in all s and p valence electrons in a shell gives eight electrons--- True
boron compounds are frequent exceptions to the octet rule because they have too few electrons surrounding the boron......True
compounds in which nitrogen is the central atom are frequent exceptions to the octet rule because they have too many electrons surrounding the nitrogen...... false
the si in sih4 does not follow the octet rule because hydrogen is in an unusual oxidation state......false
Explanation:
The octet rule simply means that atoms tend to be stable when they have eight electrons in their outermost shell. This rule mostly applies to the s and p orbitals and not to the d and f orbitals. The sum of the total electrons in the outermost s and p orbitals is often equal to eight for an atom to be considered stable, for example, the noble gases.
Boron often forms compounds which has less than eight electrons around the boron central atom because the compounds of boron often have a sextet of electrons owing to the fact that boron is trivalent and forms mostly covalent compounds.
Nitrogen compounds mostly obey the octet rule and do not have excess electrons. The oxidation state of hydrogen in SiH4 is not unusual.
