객관식
A neutral fluorine atom (F) has atomic number . How many electrons does it contain?
85
views
9. Electrons in Atoms and the Periodic Table
Electronic Structure: Number of Electrons
Multiple Choice
Which neutral element has 18 electrons?
A
Argon (Ar)
B
Calcium (Ca)
C
Potassium (K)
D
Chlorine (Cl)
검증된 단계별 안내1
Recall that a neutral atom has an equal 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: Argon (Ar) = 18, Calcium (Ca) = 20, Potassium (K) = 19, Chlorine (Cl) = 17.
Compare the atomic numbers to the given number of electrons (18) to find the matching element.
Conclude that the element with 18 electrons (and thus atomic number 18) is Argon (Ar).
Related Videos
Related Practice
