(N/A) In quantum mechanics,the wave function $\psi$ represents the amplitude of the electron wave.
The $+ve$ and $-ve$ signs do not represent electrical charges.
Instead,they represent the phase of the wave function.
$+$ indicates a positive phase (crest),and $-$ indicates a negative phase (trough).
These signs are crucial in determining the nature of orbital overlap:
$1$. Constructive interference occurs when lobes of the same sign overlap ($+ / +$ or $- / -$),leading to bonding molecular orbitals.
$2$. Destructive interference occurs when lobes of opposite signs overlap $(+ / -)$,leading to antibonding molecular orbitals.