객관식
Why is the configuration of electrons in an atom's outer shell important?
135
views
10. Periodic Properties of the Elements
Valence Electrons of Elements
객관식
An atom has an atomic number of 7. What is the most likely number of valence electrons for this atom?
A
2
B
7
C
1
D
5
검증된 단계별 안내1
Identify the element based on its atomic number. The atomic number 7 corresponds to the element nitrogen (N).
Recall that the atomic number tells you the number of protons, and for a neutral atom, it also equals the number of electrons.
Determine the electron configuration of nitrogen by filling the electron orbitals in order: 1s, 2s, 2p, etc.
Write the electron configuration for nitrogen: \$1s^2 2s^2 2p^3$.
Recognize that valence electrons are the electrons in the outermost shell (highest principal quantum number). For nitrogen, the outermost shell is the second shell, which contains \$2s^2 2p^3$, totaling 5 valence electrons.
