Making repeated separations of the various substances in the pitchblende, Marie and Pierre used the Curie electrometer to identify the most radioactive fractions. They thus discovered that two fractions, one containing mostly bismuth and the other containing mostly barium, were strongly radioactive.
<h3>What was surprising about pitchblende?</h3>
Since it was no longer appropriate to call them “uranic rays,” Marie proposed a new name: “radioactivity.”
Even more surprising, Marie next found that a uranium ore called pitchblende contained two powerfully radioactive new elements: polonium, which she named for her native Poland, and radium.
<h3>Why is radium more radioactive than uranium?</h3>
It is 2.7 million times more radioactive than the same molar amount of natural uranium (mostly uranium-238), due to its proportionally shorter half-life.
Learn more about highly radioactive elements here:
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brainly.com/question/10257016</h3><h3 /><h3>#SPJ4</h3>
Answer:
The change in entropy is -1083.112 joules per kilogram-Kelvin.
Explanation:
If the water is cooled reversibly with no phase changes, then there is no entropy generation during the entire process. By the Second Law of Thermodynamics, we represent the change of entropy (
), in joules per gram-Kelvin, by the following model:
(1)
Where:
- Mass, in kilograms.
- Specific heat of water, in joules per kilogram-Kelvin.
, 
- Initial and final temperatures of water, in Kelvin.
If we know that 
, 
, 
and 
, then the change in entropy for the entire process is:
The change in entropy is -1083.112 joules per kilogram-Kelvin.
Answer:
Some of the physical changes used by the industrial chemist in order to identify it is by scratching it with other metals in order to find the hardness of it. Trying to deform it in order to find the malleability, and to heat it and measure the temperature in order to find the melting point.
Some of the chemical changes used by the industrial chemist in order to identify it is by inserting it in water to observe that whether it reacts with it or not, if the reaction is violent, then the metal belongs to either group I or group II. The other method is to insert it in acids of distinct strength and to observe its reaction. The metals belonging to the second group react briskly with acids. The other metals react gradually with acids and others are almost inert.
Answer:
Silver has to give up one electron.
Explanation:
Silver is a transition element and has a partially filled 4d- orbital having 9 electrons and a 5s orbital having 2 electrons in it. In order to achieve stability, silver must have completely filled d-orbital having a maximum number of 10 electrons in it.
Therefore, one electron from 5s orbital jumps to 4d orbital to make it stable. Now, 5s orbital has only one electron, and it will be easy for silver to lose this electron to attain a stable electronic configuration.
