The thermal decomposition of phosphine (ph3) into phosphorus and molecular hydrogen is a first-order reaction: 4ph3(g) → p(g) + 6h2(g) the half-life of the reaction is 35.0 s at 680°c. calculate the first-order rate constant for the reaction:

If we need to get K ( the first order constant rate ) and when we have
t(1/2) = 35 s as a given so we will use this formula:

t(1/2) = ㏑2 / K
by substitution:
35 = (0.693) / K
∴ K = (0.693) / 35
      = 0.0198  s^-1

There is one s orbital, and there are three p orbitals, five d orbitals, and seven f orbitals. thus, the answer is b. do not confuse the number of orbitals in a subshell with the number of electrons the subshell can hold. each orbital can hold two electrons, so the capacity of an nf subshell is 14 electrons.

Idon’t know sorry i don’t know the answer i’m s sorry