Correct answer: B. Paleozoic. I took the test and it was right.
An element’s atomic number is equal to the number of protons in that element’s nucleus. The mass number is the total number of an atom’s protons and neutrons. Protons have a positive charge; electrons have a negative charge; and neutrons are electrically neutral.
Putting it all together, given that the atomic number of lead is 82, the number of protons a lead atom contains is 82. The number of neutrons would be the difference between 207 and 82, or 125 neutrons. Finally, since you have a neutral atom, there must be an equal number of electrons as the number of protons—that is, 82 electrons.
Thus, you’ve got 82 protons, 125 neutrons, and 82 electrons.
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Answer:
-74.6 kj/mol
Explanation:
you can see the answer at the pic
Answer:
Sodium hydroxide reacts with iron(III) chloride to produce iron(III) hydroxide and sodium chloride.
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