- Electron precise hydrides are those in which the total number of valence electrons equals the sum of the bonding electrons around the central atom.
- Group 14 elements form typical electron precise hydrides like CH₄ (methane), where each hydrogen atom contributes 1 electron and carbon contributes 4, making a stable electron count of 8 around carbon.
If uncertainty in position and momentum of an electron are equal, then uncertainty in its velocity is:
The graph shown below represents the variation of probability density, \( \Psi(r) \), with distance \( r \) of the electron from the nucleus. This represents:

Match the following elements with their correct classifications:
