Multiple Choice
Which of the following represents the valence electron configuration for a krypton (Kr) atom?
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10. Periodic Properties of the Elements
Valence Electrons of Elements
Multiple Choice
How many valence electrons does a boron (B) atom have?
A
4
B
2
C
3
D
5
Verified step by step guidance1
Identify the atomic number of boron (B), which is 5. This means boron has 5 electrons in total.
Recall that valence electrons are the electrons in the outermost shell (energy level) of an atom.
Determine the electron configuration of boron: 1s\^2 2s\^2 2p\^1.
Recognize that the first shell (1s) is full and not part of the valence shell; the valence shell is the second shell (2s and 2p orbitals).
Count the electrons in the second shell: 2 electrons in 2s and 1 electron in 2p, totaling 3 valence electrons.
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