Answer:
18 electrons
Explanation:
Note: The third energy level can actually hold up to 18 electrons, so it is not really filled when it has 8 electrons in it.
The difference in the reactivity of metals accounts for why some metals will react with hot water but not with cold water. For example, aluminum is less reactive than sodium and will only react with hot water but not cold water.
<h3>What is reactivity of metals?</h3>
The reactivity of metals is the ability of a metals to lose electrons.
The reactivity of metals generally decreases from left to right across the periodic table but increases on going down a group.
Due to the differences in reactivity of metals, some metals are more reactive than others.
For example, the reactive metals sodium, potassium and calcium react with cold water to with differing degree of spontaneity to liberate hydrogen.
Some other metal like aluminum, zinc, and iron can only react with hot water or steam to liberate hydrogen.
Therefore, the reactivity of a metal will determine if it will react with cold water or hot water.
Learn more about reactivity of metals at: brainly.com/question/28107797
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The Arrhenius Theory
The Brönsted-Lowry Theory
The Lewis Theory
(let me know if needed explanation)
Answer:
The artifact is 570 years old. That is, 5.7 × 10² years.
Explanation:
Radioactive decay follows first order reaction kinetics.
Let the initial activity for fresh Carbon-14 be A₀
And the activity at any other time be A
The rate of radioactive decay is given by
dA/dt = - KA
dA/A = - kdt
Integrating the left hand side from A₀ to A₀/2 and the right hand side from 0 to t(1/2) (where t(1/2) is the radioactive isotope's half life)
In [(A₀/2)/A₀] = - k t(1/2)
In (1/2) = - k t(1/2)
- In 2 = - k t(1/2)
k = (In 2)/t₍₁,₂₎
t(1/2) is given in the question to be 5.73 × 10³ years
k = (In 2)/5730 = 0.000121 /year
dA/A = - kdt
Integrating the left hand side from A₀ to A and the right hand side from 0 to t
In (A/A₀) = - kt
A/A₀ = e⁻ᵏᵗ
A = A₀ e⁻ᵏᵗ
A = 2.8 × 10³ Bq.
A₀ = 3.0 × 10³ Bq.
2.8 × 10³ = 3.0 × 10³ e⁻ᵏᵗ
0.9333 = e⁻ᵏᵗ
e⁻ᵏᵗ = 0.9333
-kt = In 0.9333
- kt = - 0.06899
t = 0.06899/0.000121 = 570.2 years = 5.7 × 10² years
