Here's how to determine the number of valence electrons in phosphoric acid (H₃PO₄):

1. Identify the elements:

* Hydrogen (H): Group 1, 1 valence electron

* Phosphorus (P): Group 15, 5 valence electrons

* Oxygen (O): Group 16, 6 valence electrons

2. Calculate the total valence electrons:

* Hydrogen: 3 H atoms * 1 valence electron/atom = 3 valence electrons

* Phosphorus: 1 P atom * 5 valence electrons/atom = 5 valence electrons

* Oxygen: 4 O atoms * 6 valence electrons/atom = 24 valence electrons

3. Add the valence electrons together:

3 + 5 + 24 = 32 valence electrons

Therefore, phosphoric acid (H₃PO₄) has 32 valence electrons.