Multiple Choice
How many electrons are in the nucleus of an atom with an atomic number of 20?
2. Atoms & Elements
The Atom
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Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
What does the atomic number of an element indicate?
A
The number of protons in the nucleus of an atom
B
The number of electrons in a neutral atom
C
The total number of protons and neutrons in an atom
D
The number of neutrons in the nucleus of an atom
Verified step by step guidance1
The atomic number of an element is a fundamental property that defines the element. It is denoted by the symbol Z.
The atomic number indicates the number of protons in the nucleus of an atom. This is a unique identifier for each element, as no two different elements have the same number of protons.
In a neutral atom, the number of electrons is equal to the number of protons. Therefore, the atomic number also tells us the number of electrons in a neutral atom.
The atomic number does not provide information about the total number of protons and neutrons (which is the mass number) or the number of neutrons alone.
Understanding the atomic number is crucial for identifying elements and predicting their chemical behavior, as it determines the element's position in the periodic table.
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