To determine the total number of valence electrons in the molecule H3PO4 (phosphoric acid), we need to consider the valence electron contributions from each atom.
In H3PO4:
- Hydrogen (H) is in Group 1 of the periodic table and has 1 valence electron per atom. Since there are 3 hydrogen atoms, the total contribution is 3 × 1 = 3 valence electrons.
- Phosphorus (P) is in Group 15 and has 5 valence electrons per atom.
- Oxygen (O) is in Group 16 and has 6 valence electrons per atom. Since there are 4 oxygen atoms in H3PO4, the total contribution is 4 × 6 = 24 valence electrons.
Adding up the contributions, we get: 3 (hydrogen) + 5 (phosphorus) + 24 (oxygen) = 32 valence electrons.
Therefore, the total number of valence electrons in the molecule H3PO4 is 32.