The water and heathfshiccu
Answer:
2
Explanation:
Each orbital can hold two electrons. One spin-up and one spin-down.
Answer:
4.05 × 10²² atoms
Explanation:
Step 1: Given data
Mass of nickel: 3.95 g
Step 2: Calculate the moles corresponding to 3.95 g of nickel
The molar mass of nickel is 58.69 g/mol.
3.95 g × (1 mol/58.69 g) = 0.0673 mol
Step 3: Calculate the atoms in 0.0673 moles of nickel
We will use Avogadro's number: there are 6.02 × 10²³ atoms of nickel in 1 mole of atoms of nickel.
0.0673 mol × (6.02 × 10²³ atoms/1 mol) = 4.05 × 10²² atoms
It would take 147 hours for 320 g of the sample to decay to 2.5 grams from the information provided.
Radioactivity refers to the decay of a nucleus leading to the spontaneous emission of radiation. The half life of a radioactive nucleus refers to the time required for the nucleus to decay to half of its initial amount.
Looking at the table, we can see that the initial mass of radioactive material present is 186 grams, within 21 hours, the radioactive substance decayed to half of its initial mass (93 g). Hence, the half life is 21 hours.
Using the formula;
k = 0.693/t1/2
k = 0.693/21 hours = 0.033 hr-1
Using;
N=Noe^-kt
N = mass of radioactive sample at time t
No = mass of radioactive sample initially present
k = decay constant
t = time taken
Substituting values;
2.5/320= e^- 0.033 t
0.0078 = e^- 0.033 t
ln (0.0078) = 0.033 t
t = ln (0.0078)/-0.033
t = 147 hours
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