Multiple Choice
In the context of the periodic table and element symbols, which element is commonly used for shiny trim on cars (often as chrome plating)?
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4. Atoms and Elements
Periodic Table: Element Symbols
Multiple Choice
Which element (neutral atom) has 18 electrons?
A
Potassium (K)
B
Chlorine (Cl)
C
Calcium (Ca)
D
Argon (Ar)
Verified step by step guidance1
Recall that a neutral atom has the same number of protons and electrons.
Identify the atomic number of each element, which equals the number of protons (and electrons in a neutral atom).
Look up the atomic numbers: Potassium (K) is 19, Chlorine (Cl) is 17, Calcium (Ca) is 20, and Argon (Ar) is 18.
Compare these atomic numbers to the number of electrons given (18) to find the matching element.
Conclude that the element with 18 electrons is the one with atomic number 18, which is Argon (Ar).
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