객관식
Which of the following statements is correct regarding the relationship between atoms and molecules?
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2. Chemistry
Atoms - Smallest Unit of Matter
객관식
How many valence electrons does an atom with five total electrons have?
A
5.
B
7.
C
3.
D
2.
E
1.
검증된 단계별 안내1
Identify the element based on the total number of electrons. An atom with five total electrons is likely to be boron, which has an atomic number of 5.
Determine the electron configuration of the element. For boron, the electron configuration is 1s2 2s2 2p1.
Understand that valence electrons are the electrons in the outermost shell of an atom. For boron, the outermost shell is the second shell.
Count the electrons in the outermost shell. In boron, the second shell contains 2s2 and 2p1, which adds up to 3 valence electrons.
Conclude that an atom with five total electrons, like boron, has 3 valence electrons.
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