Basically since potassium chloride is an ionic compound as it consists of a metal and a nonmetal, the potassium atom will donate one of its valence electrons to chlorine that will accept it and as a result produce oppositely charged ions, where the K + ion and the Cl - ion will attract forming an ionic bond. The compound that results is potassium chloride.
First choice: PhH4 has a lower boiling point
Second: SiF4 higher
Third: CBr4 higher
Answer:

Explanation:
1. Calculate the decay constant
The integrated rate law for radioactive decay is 1

where
A₀ and A_t are the counts at t = 0 and t
k is the radioactive decay constant

2. Calculate the half-life

The half-life for decay is
.