Answer is: <span>sp3 on nitrogen overlaps with 1s on hydrogen. </span>Electron
configuration for nitrogen: ₇<span>N
1s² 2s² 2p³. </span>Electron
configuration for hydrogen: ₁H 1s¹. <span>The central atom in ammonia, nitrogen, is </span><span>sp3 </span>hybridized (<span>one </span>s<span> and three </span>p-orbitals<span> will combine for a four sp3 </span><span>hybridized orbitals), because sp3 orbitals have lower energy</span>.