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Multiple Choice
To fill the valence shell, an electrically neutral, unbonded atom with atomic number 8 must add how many electrons?
A
6 electrons
B
1 electron
C
8 electrons
D
2 electrons
Verified step by step guidance
1
Identify the element with atomic number 8, which is oxygen. Oxygen has 8 protons and, in a neutral atom, 8 electrons.
Determine the electron configuration of oxygen to understand its valence shell. The configuration is 1s\^2 2s\^2 2p\^4, meaning the first shell is full and the second shell has 6 electrons.
Recall that the valence shell for oxygen is the second shell, which can hold a maximum of 8 electrons (2 in the 2s subshell and 6 in the 2p subshell).
Calculate how many electrons oxygen needs to fill its valence shell by subtracting the current number of valence electrons (6) from the maximum capacity (8): 8 - 6 = 2 electrons.
Conclude that oxygen must gain 2 electrons to fill its valence shell and achieve a stable, noble gas electron configuration.