A) 21
Explanation:
The difference between the number of electrons in an atom of selenium and the number electrons in an atom of Aluminium is 21;
The number of electrons in Aluminium is 13
Selenium is 34
Since the atoms are considered here, their atomic number, number of protons and number of electrons are the same.
It is only when we are considering ions that the number of electrons differ from the atomic number/ number of protons.
Difference = 34 - 13 = 21
We clearly see that selenium is 13 electrons more than aluminium.
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Subatomic particles brainly.com/question/2757829
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Answer: The kinetic theory of matter states that all matter is made of small particles that are in random motion and that have space between them. And since gases have even more energy than liquids, their particles are moving around a lot more, too.
Explanation:
I think it’s SO2 Im not quite sure but I think so