Multiple Choice
Dalton used the lightest element as his standard for atomic mass. What is this element?
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4. Atoms and Elements
Atomic Theory
Struggling with Introduction to Chemistry?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
In modern atomic theory, all atoms of the same element have the same what?
A
Mass number
B
Number of neutrons
C
Number of protons (atomic number)
D
Number of electrons in all circumstances
Verified step by step guidance1
Understand that in modern atomic theory, atoms of the same element are defined by a specific characteristic that distinguishes them from atoms of other elements.
Recall that the atomic number, which is the number of protons in the nucleus of an atom, uniquely identifies an element.
Recognize that while the mass number and number of neutrons can vary among atoms of the same element (these variations are called isotopes), the number of protons remains constant.
Note that the number of electrons can change in ions, so it is not a reliable identifier for all atoms of the same element.
Conclude that all atoms of the same element have the same number of protons, also known as the atomic number.
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