Answer:
9 . this was not able the first one. it has to go on, I will not sure about
Number of alpha decays is 4.
₉₀Th²³² → ₂He⁴ + ₈₈Ra²²⁸ ∴ α = ₂He⁴
Since, atomic number change by 2 in each alpha decay.
Total charge = 90 -82 = 8
Number of alpha decay = 8/2 = 4.
Alpha decay or α-decay is a type of radioactive decay wherein an atomic nucleus emits an alpha particle (helium nucleus) and thereby transforms or 'decays' into a extraordinary atomic nucleus, with a mass wide variety this is decreased through 4 and an atomic wide variety this is decreased through two.
Alpha decay - A common mode of radioactive decay wherein a nucleus emits an alpha particle (a helium-four nucleus). Beta decay - A commonplace mode of radioactive decay in which a nucleus emits beta particles. The daughter nucleus will have a better atomic number than the original nucleus.
Learn more about alpha decays here:- brainly.com/question/1898040
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Answer: By carrying out series of wet test
Explanation: Dissolve the ionic compound in water. Ionic compounds will ionise and allow the solution to conduct an electric current. Afterwards specific test will be carried out to detect the presence of cations and anions. Another way would be to find the substance's melting point. Ionically bonded compounds have much higher melting points.
Answer:
- <em>He realized that some elements had not been discovered.</em>
Explanation:
Some scientists that tried to arrange the list of elements known before Mendeleev include Antoine Lavoisier, Johann Döbereiner, Alexandre Béguyer de Chancourtois, John Newlands, and Julius Lothar Meyer.
<em>Dimitri Mendeleev</em> was so succesful that he is recognized as the most important in such work.
Mendeleev by writing the properties of the elements on cards elaborated by him, and "playing" trying to order them, realized that, some properties regularly (periodically) repeated.
The elements were sorted in increasing atomic weight (which is not the actual order in the periodic table), but when an element did not meet the pattern discovered, he moved it to a position were its properties fitted.
The amazing creativity of Mendeleev led him to leave blanks for what he thought were places that should be occupied by elements yet undiscovered. More amazing is that he was able to predict the properties of some of those elements.
When years after some of the elements were discovered, the genius of Mendeleev was proven because the "new" elements had the properties predicted by him.
Answer:
The term Decimal is coined from the word Decimus. Decimus is a Latin word which means ‘tenth’.
The Decimal system is a system of numbering that is based on multiples of tens. It is flexible and easy to convert from one metric to another.
The preference of the term over the Metric System is because the word Metric is related more to the measurement of lengths if we looked at the origin of the word which is French.
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