Answer:
Potassium
Explanation:
As potassium is larger than sodium, potassium's valence electron is at a greater distance from the attractive nucleus and is so removed more easily than sodium's valence electron. As it is removed more easily, it requires less energy, and can be said to be more reactive.
Time to decay : 2040 years
Further explanation
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually radioactive elements have an unstable atomic nucleus.
The main particles are emitted by radioactive elements ,so that they generally decay, are alpha (α), beta (β) and gamma (γ) particles
General formulas used in decay:
T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
moles zirconium :

moles niobium :

the half-life of niobium-91 is 680 years
Reaction
⁹¹₄₁Nb ⇒⁹¹₄₀Zr + ₁⁰e
Amount of Nb from reaction : 0.169
Amount of initial Nb = 0.0242 + 0.169 = 0.1932
Time to decay (T) :

Answer:
Both are only physical changes.
Explanation:
Nothing about the objects chemically change, and they remain the same.
Their changes arent due to heating/cooling.
P1V1 = P2V2
Convert 248mm Hg to atm
248/760 = 0.326 atm
(0.326 atm • 1.05L) / 3.98L = 0.0861 atm
Answer:
divide 10.0g by each reactant's respective molar mass then divide that number by its coefficient in the balanced reaction. the smaller of the two numbers indicates the limiting reactant - it’s Al