Answer:
Explanation:
The<em> half-life </em>time of a radiactive isotope (radioisotope) is a constant value, meaning that the amount of the radioisotope that decays will be (1/2) raised to the number of half-lives passed.
Naming A₀ the initial amount to the radioisotope, you can build this table to find the amount left.
Number of half-lives amount of radiosotope left
0 A₀
1 (1/2) × A₀
2 (1/2)×(1/2)×A₀ = (1/2)² × A₀
3 (1/2)³ ×A ₀
4 (1/2)⁴ × A₀
n (1/2)ⁿ × A₀
Now calculate the number of half-lives the strontium-90 sample has passed after 100 years:
- n = 100 years / 28.1 years ≈ 3.5587
Hence, the amount of strontium-90 is:
In percent, that is:
Rounding to two significant figures, that is 8.5%.
<u>Conclusion</u>: <em>The percent of strontium-90 left after 100 yeaers is 8.5% </em>(choice number 4).
Answer:
A) They get oxidized into carbon monoxide and carbon dioxide by the oxygen molecules generated on the electrode.
Explanation:
In the electrolysis of Aluminium, the oxygen reacts with the carbon anodes forming carbon dioxide. That is, the anodes are oxidized. To ensure that the reaction completes, the anode must gradually be replaced as the reaction proceeds. The correct option is hence;
A) They get oxidized into carbon monoxide and carbon dioxide by the oxygen molecules generated on the electrode.
Answer:
you have school on Sunday?
Answer:
Elements with low ionization energies.
Explanation:
The ionization energy of an atom reffers to the amount of energy that is required to remove an electron from the gaseous form of that atom or ion.
The greater the ionization energy, the more difficult it is to remove an electron. The ionization energybis one of the indicator that shows the reactivity of an element. Elements with a low ionization energy such as metals are usually reffered to as a reducing agents and form cations, this give metals the tendency to
give away their valence electrons when bonding, whereas non-metals tend to take electrons.
Metallic elements have different properties such as shiny, heat and electricity conductivity . They are malleable and ductile Some metals, such as sodium, are soft and can be cut with a knife. while some are very hard such as iron.
