How many valence electrons does NaHCO3 have?
The correct answer and explanation is:
The compound sodium bicarbonate (NaHCO₃) consists of sodium (Na), hydrogen (H), carbon (C), and oxygen (O). To determine how many valence electrons NaHCO₃ has, we must count the valence electrons of each atom in the compound.
- Sodium (Na): Sodium is an alkali metal in Group 1 of the periodic table. It has 1 valence electron in its outermost shell.
- Hydrogen (H): Hydrogen belongs to Group 1 and has 1 valence electron.
- Carbon (C): Carbon is in Group 14 and has 4 valence electrons.
- Oxygen (O): Oxygen is in Group 16 and has 6 valence electrons. Since there are three oxygen atoms in NaHCO₃, the total valence electrons from oxygen is 6 × 3 = 18.
Now, adding up the valence electrons from all atoms:
- Sodium: 1 valence electron
- Hydrogen: 1 valence electron
- Carbon: 4 valence electrons
- Oxygen (3 atoms): 18 valence electrons
Therefore, the total number of valence electrons in NaHCO₃ is:
1 (Na) + 1 (H) + 4 (C) + 18 (O) = 24 valence electrons.
These 24 valence electrons are distributed among the atoms in the molecule to form covalent bonds between hydrogen, carbon, and oxygen, while sodium forms an ionic bond with the bicarbonate ion (HCO₃⁻). Sodium donates its single valence electron to the bicarbonate ion, leaving the bicarbonate ion with a net charge of -1.
In summary, NaHCO₃ has a total of 24 valence electrons that participate in bond formation, with sodium contributing its electron to form an ionic bond and the rest of the atoms forming covalent bonds to achieve stability.