According to molecular orbital theory, which of the following is true with respect to $Li_2^+$ and $Li_2^-$ ?
(1) Both are unstable
(2) $Li_2^+$ is unstable and $Li_2^-$ is stable
(3) $Li_2^+$ is stable and $Li_2^-$ is unstable
(4) Both are stabel
(1) Both are unstable
(2) $Li_2^+$ is unstable and $Li_2^-$ is stable
(3) $Li_2^+$ is stable and $Li_2^-$ is unstable
(4) Both are stabel