Which of the following atoms is paramagnetic?

• A. O (oxygen)
• B. Ne (neon)
• C. He (helium)
• D. Zn (zinc)

Answer: (A)

Verified step by step guidance

1. Recall that an atom is paramagnetic if it has one or more unpaired electrons in its electron configuration, which causes it to be attracted to a magnetic field.
2. Write the electron configurations for each atom: \\ \\ O (oxygen): 1s\\^2 2s\\^2 2p\\^4 \\ Ne (neon): 1s\\^2 2s\\^2 2p\\^6 \\ He (helium): 1s\\^2 \\ Zn (zinc): [Ar] 3d\\^{10} 4s\\^2
3. Analyze the electron configurations to identify unpaired electrons: \\ - Oxygen has 4 electrons in the 2p subshell, which can hold 6 electrons, so it has unpaired electrons. \\ - Neon has a full 2p subshell, so all electrons are paired. \\ - Helium has a full 1s subshell, so all electrons are paired. \\ - Zinc has a full 3d subshell and a full 4s subshell, so all electrons are paired.
4. Conclude that the atom with unpaired electrons, and therefore paramagnetic, is oxygen (O).
5. Remember that paramagnetism arises from unpaired electrons, so checking the electron configuration for unpaired electrons is the key step in identifying paramagnetic atoms.