Identify the correct order in which the covalent radius of the following elements increases:
1. Ti           2. Ca           3. Sc

1, 3, 2

The correct asnwer is option 3. 1, 3, 2

The correct order in which the covalent radius of the following elements increases is:

1. Ti < 3. Sc < 2. Ca

Covalent radius decreases as you move from left to right across a period in the periodic table because the number of protons in the nucleus increases, which increases the attractive force between the nucleus and the electrons. Therefore, the covalent radius of Ti is smaller than Sc, and the covalent radius of Sc is smaller than Ca.

Here is a table of the covalent radii of Sc, Ca, and Ti:

The covalent radius of Ti is 1.36 pm, the covalent radius of Sc is 1.44 pm, and the covalent radius of Ca is 1.74 pm. This agrees with the order we predicted, which is 1. Ti < 3. Sc < 2. Ca.