Dots are used to represent electrons.
Answer:
False
Explanation:
Forms of a given element that have a different number of neutrons are called isotopes.
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:
<h3>
brainly.com/question/10257016</h3><h3 /><h3>#SPJ4</h3>
Answer:
Ca3P2
Explanation: find out what 66% of the molar weight of the molecule is and then find out how many moles of Ca that would be by dividing it by the molar weight of Ca
then do the same for P
The correct answer is letter (d.) Mg, Ca, Sr, Ba
These four elements are found in Group 2 of the periodic table, which are alkaline metals, therefore they have the very similar properties because of their 2 valence electrons, which makes them reactive.
