Multiple Choice
Astatine has 85 protons. What is its atomic number?
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2. Atoms & Elements
The Atom
Multiple Choice
The atomic number of oxygen is 8. What is the mass number of an oxygen atom with 7 neutrons?
A
15
B
7
C
16
D
8
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Verified step by step guidance1
Recall that the atomic number (Z) represents the number of protons in an atom. For oxygen, Z = 8, so it has 8 protons.
Understand that the mass number (A) is the total number of protons and neutrons in the nucleus of an atom.
Use the formula for mass number: \(A = Z + N\), where \(N\) is the number of neutrons.
Substitute the given values into the formula: \(A = 8 + 7\).
Add the numbers to find the mass number, which represents the total nucleons in this oxygen atom.
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