Open Question
Indicate if the atoms in each pair have the same number of protons, neutrons, or electrons. (4.4, 4.5)c. ⁴⁰₁₈Ar, ³⁹₁₇Cl
2. Atoms and the Periodic Table
Isotopes
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Which of the following answers give the correct number of subatomic particles for 
?
A
34 protons, 34 neutrons and 34 electrons
B
50 protons, 18 neutrons and 18 electrons
C
16 protons, 18 neutrons and 16 electrons
D
17 protons, 17 neutrons and 17 electrons
Verified step by step guidance1
Identify the element from the symbol 'S'. The symbol 'S' stands for sulfur.
Determine the atomic number from the subscript. The subscript '16' represents the atomic number, which is the number of protons in the nucleus of the atom.
Determine the mass number from the superscript. The superscript '34' represents the mass number, which is the sum of protons and neutrons in the nucleus.
Calculate the number of neutrons by subtracting the atomic number from the mass number: Neutrons = Mass number - Atomic number = 34 - 16.
Since the atom is neutral, the number of electrons equals the number of protons. Therefore, there are 16 electrons.
