Answer:
230
Th
90
Explanation:
The left side shows the element uranium with mass number 234 (superscript to the left of ths symbol) and atomic mass 92 (subscript to the left of the symbol).
So, you have to find the mass number and atomic numbers missing on the right side which added to those shown for the helium atom reach 234 and 92.
This the the mathematics:
1) Mass number of U - mass number of He = 234 - 4 = 230 ⇒ the mass number of the missing element is 230.
2) atomic number of U - atomic number of He = 92 - 2 = 90 ⇒ the atomic number of the missing element is 90.
Now, you use the atomic mass to identify the element. You do it by simply searching in a periodic table. There you find that the atomic number 90 corresponds to thorium, whose symbol is Th.
Now you have that the product that completes the right side of the decay equation is:
230
Th
90
I would say that it is physical because there are no chemicals when the glass is breaking.
<em>HOPE I HELPED!!!</em>
The statement that best describes the variables in a controlled experiment is independent variable while all other conditions are unchanged.
<h3>What is an experiment?</h3>
An experiment is a scientific research, findings or investigation about a subject matter with the aim of validating a claim and establishing theories.
A controlled experiment refers to an experiment in which the variables involved and the control factor are kept in the same group except for one variable which can be changed.
Therefore, The statement that best describes the variables in a controlled experiment is independent variable while all other conditions are unchanged.
Learn more about experiment below.
brainly.com/question/25303029
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