Consider the orthosilicate (Sio anion. What is the central atom? Enter its chemical symbol. How many lone pairs are around the central atom? 0 What is the ideal angle between the silicon-oxygen bonds? 囗'. 。 Compared to the ideal angle, you would expect the actual angle between the silicon-oxygen bonds to (choose o be. one) !

Si; none; 109.5°; the same

Explanation:

1. Central atom

The formula for the orthosilicate ion is SiO₄⁴⁻.

The central atom is the atom with the smaller electronegativity.

Electronegativities are: Si = 1.90; O = 3.44.

Si is less electronegative, so Si is the central atom.

2. Draw an electron-dot structure

(a) Count the valence electrons

1 * Si (Group 14) = 4

4 * O (Group 16) = 4 * 6 = 24

+4 e⁻ (for the charges) = 4

Total = 32

(b) Draw a trial structure

Put Si in the middle with four bonds to O.

Give every atom an octet.

(c) Count the valence electrons

Valence electrons = bonding pairs + lone pairs

VE = BP + LP = 4BP + 12LP = 8 + 24 = 32 electrons

The number of electrons in the structure equals the number of electrons available.

The trial structure is correct.

The central atom (Si) has no lone pairs.

3. Theoretical bond angles

A molecule with four bonding pairs and no lone pairs about the central atom has a tetrahedral shape. The ideal bond angles are 109.5°.

4. Actual Bond Angles

The orthosilicate ion has tetrahedral symmetry.

The actual bond angle should be the same as the ideal bond angle (109.5°).